Minho walks into the room amazed at seeing a new boy, so Thomas gives them the old, "Minho, meet Aris... Aris, meet Minho" (5.9).
Teresa's still gone, so Thomas quickly tells everyone to search for her in another room. But there aren't any other rooms; Minho checked.
Everything is locked from the inside, which is strange.
Thomas has a sinking feeling that Teresa is one of the dead bodies—but he checks, and she isn't.
The boys interrogate Aris to figure out his situation.
Apparently, Aris was in the Maze, but he was the only boy with a bunch of girls.
Hmm, so he was the male equivalent of Teresa.
Just as Aris continues his story, Newt finishes his story for him. Newt's all like, Wait, were you the last one to get there? And did you get there in a coma? And did you have a note that said you were the last one?
Remember, Newt has educated guesses because what he describes is that's exactly what happened to Teresa.
Aris is flabbergasted, and Minho shouts out that WICKED must have built two mazes with two different tests. So Aris must have been part of Group B.
Oh, and one last thing: Aris can speak telepathically, just like Thomas.
So Thomas and Aris bond for a few seconds telepathically, and Thomas learns that WICKED killed Aris's best friend, Rachel.