Somehow I don't think Michael's reason for sitting down was to 'think it over'. Once he walked into that restaurant he knew what he had to do, and that he was going to do it. The 'thinking it over' part was long past.

I would agree that Micheal just didn't have it in him to 'come out blasting'. One would guess he was a nervous wreck and simply had to sit down and gear himself up. YOu can see it all in his face.

Apple