Damian had thought about grabbing Yen-Sid just as they'd teleported, but realized that letting go for any reason would have been incredibly stupid. "Keep yer 'ead on straight" as Captain Winchester had always said, especially when Damian would start getting off task. Instead, when they arrived in the room with the boy in the bed, he moved to distract himself, playing with a length of rope by practicing his different knots, naming them quietly to himself. When Merlin led the others away, he followed, but he really just wanted a place to rest and try and piece things together. In the end, that's all he would want besides to go home.