Susie was a little nervous after Mr. Harvey had asked her if she had any boyfriends and told her that she was pretty. She finished the Coke he'd given her and said "I got to go." Mr. Harvey then replied "I don't know why you think you're leaving." Susie then kept up a running conversation - she kept talking to Mr. Harvey so that her brain would not compute the fact that she was in serious trouble. She felt that if she kept talking to him, everything would be OK.
"I talked so I would not have to take in this knowledge."
It was a way of maintaining her composure at the moment.