The precise timing of her transmigration was the day the protagonist's team of elites received Starship 549's captain's SOS. The reason their team was suspicious of Alex's group survival was because it took them sixteen days to get to the ship, resulting in twenty total days of survival.
The attack by the aliens was unexpected and originated from within the ship rather than externally. One of the researchers was jealous of the supervisor in charge because he believed that he should have been the one in charge of the research team, and due to this resentment he decided to conduct an unauthorized operation on his own and made the careless mistake of neglecting to use an anesthetic to immobilize the test subject; an egg carrier type specimen labelled a facehugger.
Before he could react, the facehugger launched itself from the operation table and latched onto his face, injecting an egg into his body orally after rendering him unconscious with its paralyzing chemicals. After this short exchange of no longer than a few seconds, it returned to the container made of indestructible transparent glass-like irudisium* that it was held in before the researcher took it out.
When the researcher woke up next, he had no recollection of the attack and was naturally unaware of carrying the egg of the alien inside him. Since he wasn't supposed to be in the lab anyway, he cleaned everything properly leaving no traces of his presence. The facehugger only died after the egg inside him already hatched and the alien tore its way out of the researcher's chest so no one found out that the facehugger had been taken out of the container and already became an empty vessel awaiting its death.
If the egg had hatched while the researcher was around others, the tragedy would not have happened, and the baby alien would have been apprehended as another specimen to bring back to the colonies. Unfortunately, it hatched during resting time while he was alone in his room and no one was there to take it into custody. In fact, the moment it hatched it went into the vents and preyed on the small vermin that should not have been there and other sleeping defenseless cannon fodder humans.
Even as a child, these aliens were formidable predators with their inhuman speed and their acidic blood in addition to their small size of one foot tall. By the time the fleet's resting period of only two hours was over, it already killed more than half of the team of researchers and became a full-sized alien at a towering eight feet tall and fifteen feet long with its tail.
Knowing full well its own superior capabilities against the powerless and unsuspecting researchers it went on a killing spree whilst freeing its compatriots that were forced into hypersleep* through anesthetics and advanced technology.
These comrades consisted of facehuggers as well as other fully-grown aliens that the researchers termed as drones and warriors. By the time the vanguard, offense corps, and the captain of the starship were notified of the breakout, it had been three days and the entire research team had already been wiped out if they were not hosting new eggs.
Left with no other choice, the captain of the ship immediately quarantined the entire research department by lowering the walls in the hallways before relaying the dire situation back home.
While the reinforced metallic malunimium* walls were far from enough to withstand the destructive force of drones and warriors forever, it could temporarily hold them off. Unfortunately, luck was not on their side as the blockade collapsed and were shredded apart within a span of fifteen days while the meet-up point with the protagonist's team was still sixteen days away.
The fleet was only able to defend themselves and survive for twelve hours before being completely wiped out.
Alex, Tyler, and Faust were originally stationed in different departments; Faust was part of the logistics team, Tyler was the captain of the vanguard, and Alex was the scientist in charge of supervising and researching the alien specimens.
In short, Alex was the most knowledgeable about their alien predators. She was also a survivor who was locked inside the research block with the aliens since day three of the massacre.
Tyler and Faust were worried for her and asked for permission to send assistance, but their pleas were ignored and could only wait for the walls to fall.
Regrettably, by the time the aliens finally broke through their barricade, Alex had already been forced into a coma by a royal facehugger for the entirety of the quarantine and housed the alien queen within her body. When she woke up fifteen days later, instead of bursting through her chest violently like the typical drones and warriors, as a highly-intelligent lifeform it chose to stay within her body and possess it as its own using it as a camouflage against the humans.
Unexpectedly, Alex's mental strength was quite high as someone who had lived a harsh life as an unwanted legitimate child of the Aldebaran family and thrown into the underground society to work as their enslaved researcher where she met her two lifelong friends, Tyler and Faust. Those two were her only reasons for continuing to live and vice-versa.
Anyway, while she could resist the queen's attempt to overtake her consciousness, she couldn't get rid of it completely like Tian Xi did, so her hormones were off the charts after it settled down. The alien queen's purpose in life, after all was to rule over and to birth more aliens.
When the two men fought their way to Alex with the maximum number of weapons they could carry by hand and luggage while still retaining mobility, the sight they were met with was one where Alex was a bloody mess--yet strangely unharmed--seated in a room full of corpses with not a single alien in sight. Although they felt that the scene was definitely off, they were just happy that their most loved one was still alive.
However, since they were the only people in the universe she cared about, Alex told them that she was hosting one of the aliens in her body, hoping they would run or kill her because she didn't know if she could resist it forever.
Of course, because of their undying love for her, they rejected both options unhesitatingly.
As she was their queen, the other aliens stayed away from her whilst protecting her from the shadows. They inherently knew that she would somehow "take care" of the two humans beside her.
In the end, she kind of did, albeit unwillingly.
As stated before, her hormones were off the charts. That, in addition to the two men's own original lust for Alex was already enough to break down the walls of friendship between the three individuals. The longer they stayed together, the stronger their desire to do things that normal friends wouldn't do with each other.
Alex knew it was the alien inside her influencing all three of them, but they really couldn't resist and ended up performing the legendary threesome.
In the process, she injected them with her own eggs of her royal guards.
When the deed was finally complete, she instantly despaired and tried to kill herself only to find out that she couldn't because she was more alien than she was human, and the queen inside her didn't allow it. So, she could only wait to see her precious friends become aliens.
Thankfully for her, the royal guards were also highly-intelligent and chose not to tear open Tyler's and Faust's chests. Because of that, the two men were able to restrain them like Alex did to the queen.
They did not sleep for as long as she did and woke up in time to bump into the protagonist's team, kickstarting the plot of the original storyline.
As soon as Alex was finished going through the world and mission details, she heard footsteps approaching. They were cautious and quiet, but as an advanced lifeform Alex's hearing was magnified by tons and knew by the that they were two males--presumably Tyler and Faust.
When they stopped in the hallway just by the mutilated malunimium door, she knew they were hesitant and on guard because of the gruesome and gory surroundings along with the chilling silence that made the entire situation eerie.
Suddenly, one of them kicked the half-closed sad excuse of a door off of its hinge and rushed in with his gun, a pulse rifle* ready to fire at any enemy that could be waiting for them.
It was Tyler, and he was stunned as he instantly froze on the spot when his eyes landed on Alex's elegantly seated figure on the blood-stained floor as if she was waiting for them. The pupils in his blue-gray eyes constricted as he quickly lowered his gun and stood stupidly still in his place. His combat suit was white, but the circular and linear designs were blue like Alex's, complimenting his short gray hair.
Noticing the oddity, Faust spoke up with his gentle and mellow voice as he prodded Tyler on his pronounced shoulder blade. He walked out from behind the slightly taller man, his soft brown hair shifted a little as he did so.
"Tyler? What's--"
He froze with his mouth still slightly open from leaving his question incomplete upon seeing the girl he had been wanting to desperately hold in his arms for the past fifteen days. His pale jade eyes widening in pleasant surprise and relief.
""Lexi...""
.
.
.
*irudisium: glass-like material that is harder than diamonds and practically impenetrable by anything aside from the all-powerful aliens.
*malunimium: highest quality reinforced steel/metal in 2940 of the Martian calendar. Usually used as the main material for starships. Extremely heavy and dense despite its durability so it is not used for the mechs and jets.
*hypersleep: term taken directly from the Aliens franchise. Basically, a coma. Except apparently those who fall into hypersleep don't age even after 50+ years.
*pulse rifle: term taken directly from the Aliens franchise. It's a gun that shoots bullets like a shotgun.