Curley tells Carlson to shoot Lennie in the guts as soon as he sees him, tells Whit to go to Soledad and get the deputy sheriff, and tells George to join the search party for Lennie.
He's not interested in hearing about how Lennie is nuts and didn't mean to do it.
Slim, looking down at the dead body, suggests perhaps Curley should stay with his dead wife and cool off.
Nope. He's hell-bent on shooting Lennie himself, even if he's only got one good hand.
And George had better join the hunting party, or everyone might start thinking that he had something to do with it.