The moment Quirrell entered the corridor, Dumbledore's eyes narrowed. He said to Professor McGonagall, "Minerva, I believe you have class in the morning."
Professor McGonagall replied, "Indeed, but never mind, I may be late-"
"That's not going to work!" Fudge immediately put on a look of distress, "We can't afford to harm the children, Transfiguration is a very important lesson, Minerva, hurry up and go to class while I discuss unicorn poaching with Professor Dumbledore."
"Go to your classes too, boy, and study hard for a job at the Ministry of Magic: if you have good grades, you could get into the Ministry of Magic!". Fudge urged Tom before leaving.
After talking to Tom, he left as quickly as he could with his subordinates and Dumbledore, who needed to go to the Ministry of Magic.
A butterfly flew out the window and landed on Professor McGonagall's hand, turning into a note with a message that read: Take Tom to that place, now!
Professor McGonagall raised her eyebrows and immediately chased Tom back to where he had gone, then stopped him just before he reached the Ravenclaw Common Room, where he was talking to Hermione.
"Tom, come with me at once." As soon as they met, Professor McGonagall said involuntarily, dragged Tom away and left.
Hermione tried to follow, but Professor McGonagall glared at her and shooed her away; Hermione was terrified of Professor McGonagall.
Tom pleaded with Professor McGonagall, "Professor, just a minute, let me go back to my dorm..." he had a good idea what he was going to do, but he still had his Uzi in his dorm! This had caught him off guard and left him without a way out. But you can't blame Tom, who carries a machine gun when they go to breakfast?
But he touched the kettle in his pocket and felt safe again.
"No, it's too late." Professor McGonagall turned him away without looking back and instead quickened her pace.
Suddenly aware of something, Tom asked tentatively, "Professor, are you..."
"Albus asked me to accompany you to fetch an important object, he said you were more familiar with the level." As they spoke, the two had reached the closed corridor on the third floor.
Professor McGonagall opened the door with a gentle push, which changed her expression: she had locked the door before leaving.
She walked over to the trapdoor and said to Tom, "Jump!"
She expected Tom to squirm and not dare to jump, but he did so without complaint. The air inside the trapdoor was damp and cold, and Tom fell for a long time before he landed on a soft mass, looked at the trapdoor directly over his head, which was now the size of a postage stamp.
It would have been easy to figure out how far he was from the ground, simply by knowing the size of the trap door, and from the size of the "postage stamp", approximate the distance, but Tom had no such idea.
Professor McGonagall jumped as well, and the moment she was on her feet, she whipped out her wand, "(Fire)!"
The flames scared away the vegetation below them.
"Devil's snare, it likes dark and damp conditions, but it's afraid of fire." He looked at Tom, "Professor Sprout should have taught you that in class, but you've been dithering, doing nothing."
"Professor, if you had taken action, I'm afraid you wouldn't be able to talk to me now." Tom was speechless: how could he not know it was the Devil's Snare? It's because you haven't jumped yet!
Professor McGonagall fell silent and then cast the spell (Lumos) to illuminate her surroundings. Below the trapdoor was a passageway, and at the bottom of the passageway was a room full of the Devil's Snare, a plant that was, in fact, quite deadly. If you didn't pay attention in herbalism class when you were a kid, even adult witches would have had to suffer here.
The exit from the room is also a long passage,
The walls of the passage are covered with moss. The passage, which did not lead downwards, was long, narrow and winding, and must have been reserved when Hogwarts was built, leading to the "subway chambers" of Hogwarts.
The professors were conscientious enough not to set any traps in the passage, and Quirrell was in such a hurry to leave that he didn't set any traps. Tom could have devised a million of them. For example, the sides of the passage would be slowly picked out until the intruders were beaten to a pulp, or the trigger would be a flash of light followed by a flying arrow: A sudden flash of light in such gloomy surroundings would probably have blinded him, or simply a dumping of quicksand....
But there were no such traps, and Tom and Professor McGonagall reached the end of the passage safe and sound. At the end was a room with a large iron cage, in front of which were five square stones with petal patterns. Inside the cage were hundreds of tiny, jewel-like birds, jingling and flying. If you look closely, the birds transform into keys.
On the other side of the room was a wooden door with a lock.
Tom was surprised as he entered: how had Quirrell managed to speed through this level?
He had helped Dumbledore design this level and the idea was simple: place the square stones in order, so that the petals of each stone would light up in the same number, so that the lock on the cage could be opened and the key would fly out, and then use the flying broom to catch the corresponding key.
In theory, Quirrell should have been trapped here for a long time, but how had Quirrell managed to clear the cage by the time Tom and Professor McGonagall arrived? Tom looked at the bird in the cage and suddenly had an idea: hadn't Quirrell reached in to get the corresponding key and get out?
Seeing the hole in the cage and the density of the keys, Tom thought it could be done.
For a moment, Tom was speechless: Quirrell, this guy, really knows how to use bugs....
But he was going to solve the puzzle the old-fashioned way, after all, he knew the standard answer. And it was clear from Professor McGonagall's blank stare that she didn't know how to solve the puzzle.
The five stones were lined up, each with three petals, some light and some dark, and Tom's goal was to get the same number of petals on each stone; the number didn't matter, one, two, three, whatever.
From left to right, the number of petals illuminated was 1, 2, 3, 2, 2, 1. The pattern of the stones was simple: each time a stone was pricked, the number of petals changed, and so did the stones on either side. However, the leftmost and rightmost stones would only change with the one next to it.
Each time a stone is struck, one is added to the number of petals it has, but if all three are lit, only one will light.
Tom stepped forward, ready to solve the puzzle.