In the figure of Lennie, who has severe learning difficulties, Crooks senses a rare opportunity to taunt the white man and get away with it. Segregated from the rest of the ranch-hands and shut away in a crummy little shack, Crooks is the victim of racial oppression, yet he never gets the opportunity to hit back.
Until now, that it is. He taunts Lennie over his dependence on George and throws out a string of hypothetical questions at him, all of which revolve around something bad happening to George. If George didn't come back to take care of Lennie, got injured, or even died, then where would Lennie be?
Lennie is upset at Crooks' taunts because he thinks that something bad really has happened to George. Realizing that the fun's over and that Lennie might just be about to do something crazy, Crooks tries to calm the big fella down. He tells Lennie that George is fine. Lennie is suitably pacified, and the brief moment of danger passes.
Yet Crooks is satisfied that he's given a valuable lesson to Lennie: now he knows what it's like to be alone, to have no one to care about you. This is how Crooks feels all day every day.