It is never a good thing when parts of the landscape stand up. Gordon goes back under the water, swimming as well as he can to get some distance from the troll.

Okay, Gordon, you have a creature made from the rocks of the earth the size of a small mountain wanting to smash your bones. Now, think, how are you going to take that down? Well, first thing to do, get some distance to get out of the water alive. So, Gordon shifts back to human form as he's not dragged down by wings and is a smaller target in this form.