Derek was sleeping. It was one of the side effects of training with Hanna. He didn't sleep a solid eight hours, but he found that he was sleeping blocks of three-four hours. He was also not using his bed, but it was still sleep, at least when he didn't stay up with Nell.
Tonight was one of those nights when he was sleeping on the floor of his room, fully dressed and rifle in his hands with the safety on. It was a very good thing, because when the scream woke him up, his finger was already on the trigger and he was out of his room in no time. He opened the door with a kick and surveyed the room, before lowering his rifle and kneeling next to Nell, not touching her. "Hey, look at me. You're okay. It was just a nightmare. Deep breaths, okay? I'm going to help you with these sheets, just don't kill me." He wasn't even joking. With her power and the state she was in, he wanted to make sure that he would still be breathing.