Light responded calmly, "We will also follow Master."
From Light's perspective, he no longer wanted to return to civilization where he had to deal with the messiness of his family situation. Moreover, he believed that with Aida around, no harm could possibly come to his two brothers. Aida felt like a warm embrace to Light, he finally felt like he could breathe again and that he wasn't trapped in endless darkness. Despite his calm facade, he was incredibly fearful of the idea of falling back into that darkness.
Nodding in satisfaction, she had indeed chosen to save the correct people. Little did she know, she would come to really appreciate this decision in the future.
"Okay, we will need to sit down and plan our actions. Before that, Yukio, I need you to come over here for a little bit."
Nodding obediently, Yukio walked over to Aida. "Open your mouth," she ordered.
He curiously, but obediently complied. Biting her finger, she purposely opened a small wound and dripped a bit of her blood into Yukio's mouth. Light watched on calmly, knowing this was the same process that she used to heal him. He firmly believed that Aida would not harm them.
After taking the blood, Yukio fainted. Aida expected this and caught him, before carrying him back into the locker room. Light and Ace followed behind.
Light's judgement was correct. In reality, Aida's blood was very special and this was one of the many reasons she tried to keep everything she did very low profile before the apocalypse. In fact, her blood is able to change the quality of all the blood cells in a person's body, much like how transfusions are used to combat diseases such as sickle cell anemia. This means she could effectively cure any blood related disease in existence.
Additionally, after the blood in a person's body is transformed, there are a few other effects. The most direct effect is that now they are directly connected to Aida in a master-slave technology relationship [1]. Ace unintentionally characterized their relationship very accurately. He was indeed the "slave" in this context. This master-slave relationship had already been demonstrated. Aida had unintentionally walked through all of Light's memories and felt Light's darkness, while Light could also subtly feel Aida's feelings. However, despite the fact that both Light and Ace had Aida's blood, they could not feel any connection between each other because they were both "slaves" in this relationship.
The second effect that the blood has is that it boosts the body's vitality. While this does not mean getting stronger or faster, it does mean that the new body could take a lot more beatings before it becomes fatal. This would be a crucial quality to survive in the apocalypse. As for the strength and speed, that could be trained and Aida had many plans to help Ace get in shape.
Lastly, and most importantly, is the time component of the blood. Rather than healing the body, her blood is able to revert the time elapsed on any object it touches back to it's optimal state. For example, when the blood entered Light's body, it is in the process of reverting his body into the time when he was physically in the best condition. Fortunately, he had always been focused on staying in top physical condition, so the blood did not take long to reach the optimal state. In fact, the blood even tried to heal his mental issues and fatigue, but the scars were so deep that it is still in the process of reverting.
This effect is not limited to just animate objects. For example, if the blood were to entirely cover a can that was crushed the day before, one would be able to watch as the can slowly reshaped itself back into the shape of a soda can. However, if the can were crushed a year before it came in contact with the blood, it would take significantly longer for it to revert its shape.
This last reason is why Aida was so confident in taking on any enemy. Even if she were shot or mortally wounded, her blood would kick into action and as long as the damage is not incurred slowly, she would recover immediately. The only way to truly kill her is to drain all the blood from her body. Given how powerful her ability is, it makes sense that she borrowed Ace's blood for the blood test upon entry into the airport. She was literally a walking cure for the virus.
Although this ability is very powerful, in the end, Aida is still only human and has limited blood within her body so unfortunately she has no way to use this skill recklessly.
Both Yukio and Rin were unconscious, which leads Aida to believe that they must have many long term internal injuries. Pondering a moment, Aida decided to inform Light of the condition of the twins as it was his right as their most loving brother and responsible guardian. He had proven his loyalty and now had a connection with her, so she trusted him to an extent.
She explained the unique quality of her blood to transform the body and heal any wounds, but withheld the explanation that it was actually manipulating time as that was a major secret of hers.
Hearing her words, Light's calm eyes blazed with anger. He realized that despite all his efforts to protect his two brothers, his relatives were still able to reach them and sneak in slow acting poison into their food. No wonder they didn't ever truly bother to act on the twins while they were living in the house. It turns out they were treating the twins as though they were already dead!
Taking a step back, this made Light all the more thankful towards Aida. Had he not met Aida, the twins would have died under his care without him ever realizing how or why. Although they had only known Aida for less than a few hours, he had wholeheartedly decided to dedicate the rest of his life to repaying this debt.
He bowed elegantly and said, "Thank you Master."
Aida side stepped to avoid both the bow and the "thank you," as she disliked both. Light didn't mind her actions as he would use actions to prove his gratitude.
[1] Master-Slave technology is a computer term that describes the relationship between a main device (ie. phone) and all the peripheral devices (ie. bluetooth devices, headphones, t.v., speakers). While the main device is able to communicate with each of the peripheral devices and vice versa, the peripheral devices are not able to communicate with each other.