Eva was still rambling as her thoughts went a million miles an hour. Will was looking a little restless. Talking about Hazel wouldn't work to occupy him much longer.
The only thing that might stop him from killing John the moment the call ended was if Hazel knew where he was right now. There was no way he would be able to get away with it if she saw him with the victim right before the crime was committed.
She knew Will held a grudge against Abramson for writing all that crap about him. She could put the pieces together.
Even if he wasn't aware she knew he was Billy Thornton, he couldn't possibly be stupid enough to kill someone right after letting his wife see who he was with, right? He had put up a front with her this long; he had to maintain the lie at all costs.
The problem was getting Hazel to cooperate. They weren't exactly on speaking terms these days. There was absolutely no guarantee she would answer the call. In fact, she probably wouldn't.