I want to root for Colossus but I don't know if there are enough feats. Him getting nailed in the face by a large rock going pretty fast would be about as good of a durability feat as any (in the danger room). I don't see the terminators dishing out anything tougher than that. But Arnie and that chick were throwing each other through concrete walls with no damage, no change of facial expression, and heck it didn't even scratch their skin much. Porcelin toilets be danged!
However, I have a feeling that Colossus can get ahold of them and pull limbs off with a good effort. I say he wins cuz they aren't going to hurt him.