He grits his teeth, already giving up in trying to swim against the pull or kicking to no avail. He wasn't going to be drowned by-- what? Hallucinations?
Even if he frantically tried to pry the the hands off him, they could just as easily come back. Pull harder. Angrier.
Instead he goes for basics; fingers to the eyes to temporarily stop an assailant. Anything at this point, since he wasn't sure he wanted to find out just how much deeper this water went when his lungs were begging for air.]