Of Mice and Men: Alternative ending

Miss Elliott

George raised the gun and steadied it, and he brought the muzzle of it close to the back of Lennie’s head. The hand shook violently.
George's finger hovers over the trigger, and then he lets out a breath, gun lowering. "I can't. I just can't do it," he murmurs, voice shaking slightly. 
Suddenly, Lennie turns his head and sees the gun pointed to his head. He lets out a fearful cry, falling back and George jerks away, eyes wide. "Wha are you doin' George? Wha' you doin' with that gun?!" Lennie yells, eyes looking wild, like a cornered animal.