DID CHRIS SAW BOTH OF THEM FUCKING NAKEDDD?!?

I think he was behind the locked door

but why chris shouted back when the uke mentioned his name while talking? (⊙…⊙ )

Because He heard them through the door? I mean He probably didn't know what to do and couldn't just return without Ilyan, but at the same time didn't want to interupt them, so i think he was just waiting for them to finish. You can see them being pressed against the door, so Chris is probably behind the door.