The Hulk wasn't going to let Bruce come back until he was sure there was no danger. That was not this situation. That wasn't even close to this situation. He looked annoyed, and confused, when Tony turned into Iron Man but it kept his attention. Iron Man he knew, so he waited. When he was told not to smash he let out a very annoyed huff and one arm swung behind him to point at the dragon monster and then he looked back at Iron Man.