Explain what happens to Curley's wife in the barn?

Lennie is in the barn, holding his dead puppy. Like the mouse he had at the beginning of the novel, the puppy had been killed by Lennie’s petting it and smacking it when it tried to bite him. He tries to hide it in the straw, but he takes it out again, asking it why it had done that, basically blaming the puppy for being killed. Curley’s wife comes in and finds Lennie with the puppy. Learning that Lennie liked to pet soft things, she told him that she knows how he feels, because she likes to feel her hair when it is clean. She has Lennie feel her hair to see, but Lennie strokes to hard. She becomes frighten and tells him to stop, but Lennie, whenever he is confronted like this, panics, and grabs hold and won’t let go. She tries to escape, and Lennie tries to stop her. Holding her roughly, Lennie breaks her neck, killing her instantly. He does not know what to do when Candy comes in and finds them. He retrieves George, who tells Lennie to run away to the spot they had agreed on should Lennie cause any trouble. George makes a plan with Candy that will prevent people from thinking that he was in on this with Lennie. The others come in, including Curley, and take off in search of Lennie in order to lynch him.