As George is readying his courage, Lennie says, "Le's do it now. Le's get that place now."
George agrees they've got to do it now, and as Lennie continues to look over the bank, envisioning the farm, George puts a gun to the back of Lennie's head and pulls the trigger.
Lennie lies still in the sand, without quivering, dead.
Ugh, Steinbeck. Could you be any more depressing?
The other men hear the shot and come running. They think that Lennie had Carlson's gun and that George wrestled it away from him.
But Slim understands. He comes over to George quietly and sits close to him, saying simply, "Never you mind…A guy got to sometimes."
As the other men probe George for the nasty details, Slim intervenes. He tells George the two of them should go for a drink, and as he helps him up adds, "You hadda, George. I swear you hadda. Come on with me." The two leave.
Carlson looks at the others and says, "Now what the hell ya suppose is eatin' them two guys?