Andy hadn't been at the Institute very long, but he'd decided that having somewhere to go was marginally better than throwing his safety to fate. He didn't feel secure at the best of times and his misstrust of people only amplified his feelings of being in danger all the time; he couldn't control it but he could pretend to himself that he could a little better in that environment.
There was also the thing about the possibility of getting his visions under control or at least being able to warn the poor victims that he saw being run over, falling down the stairs, stabbed, burned, and so on and so on. A little more secure and a little less guilt? Better than trying to survive with zero skills on the other side of the US to his so-called family home.
He didn't have a roommate when he was assigned a room, and while he'd kept to his side of the room as though someone else did use the rest of the space, the vacancy didn't bother him. He was relieved that there was no one there he'd wake up screaming or talking or by walking around while he was asleep. He felt secure about falling asleep facing the wall (not that he fell asleep facing the wall, but it was nice to have the option) or getting dressed in his room. At the same time, he was pretty lonely and so much space spent alone wasn't good for him. It gave him more time to stay in his head and stew over things that had happened, a place that even playing his guitar couldn't pull him out of.
Even so, when he was told he'd been assigned a roomie he hadn't fussed or protested but a cold feeling of dread had started to leave frost in the bottom of his stomach and shove his heart up into his throat. He was sat curled up on his bed - the corner of the room where the pillow was as he usually did, his instinct to stay small even in his own space - dressed comfortably in jogging bottoms and a hoodie and playing nothing to himself on his acoustic guitar when a knock on the door had him jumping out of his concentration.
He got up and slid off the bed like a cat, opening the door to who he thought must be his new roommate because no one else ever knocked on his door and answering with a, "Hey."