Derek is cleaning off the equipment in the main room with some disinfectant and a towel when he spots Prim enter the facility. First he waits to let her look around for a bit, unsure of whether Prim is here to work out or is looking for someone specific. He felt a very strong 'big brother' vibe toward her, knowing that she was here alone and that the world she came from wasn't that great.

So when she spots him and starts over to him, he lets her have a full grin and even reaches out to give her a one-armed hug. "Hey sweet girl. The better weather looks good on you." Eluding to how much better she looks than the last time he saw her.