"Buying time, most likely. Throwing the biggest weapon available at the problem." He wouldn't have had any 'in case of Thanos' plans ready to go. A question that presented itself: why hadn't he taken the Tesseract and fled in the Commodore while the Hulk fought and lost?

Thanos would have killed everyone and destroyed everything anyway. There would have been nothing real to be gained from running, almost certainly.

Almost. Another thing to consider. "I'm not there yet and I know your Hulk would lose."