What an Idiot: It's the dramatic conclusion of the arc, and Reed Richards is squaring off against Nihil on the Vegas Strip! The tyrant opens his mouth to devour the hero, who stops him by picking up a nearby plasma rifle and wedging it in between his jaws! You'd expect: Nihil to do literally anything except what he actually does. Literally anything else. Instead: He tries to pull the gun out...by the trigger. It's... not pretty.
The Thing, even more than in the mainstream continuity; whereas mainstream Ben has long ago accepted his transformation and even embraced it, Ultimate Ben is so depressed by his transformation that he's attempted suicide. And each one fails because his body is nigh-invincible.