Wide-open eyes would work for some parts of the film - I'm pretty sure he opens his eyes very wide when hes getting back up off the ground after Reese knocks him down with the shotgun...or I think in the parking lot when he finds them he suddenly goes big-eyed before blasting away with his own shotgun. Mostly though hes squinty eyed in T1. I hope HT knows to not give him so many frown lines and facial lines generally for T1 however.