In quick succession, Tony skepticism at Spider-Man's account of the events was replaced by guilt for doubting it and he found it safer to look back at the machine, as if that would give him the answers. Not knowing the guy didn't give Tony a free pass to project his own ills on him; Spider-Man didn't seem like the pre-meditative murdering type. He didn't seem like he pre-meditated a whole lot, really. If Spider-Man had enough experience with this Smythe guy to know what to expect, he should have had a better working plan for taking out his spider assassin. But maybe that was expecting too much.
An understanding nod was safe territory. Tony didn't like anyone telling him how to do his job, either. Jesus, projecting. "You okay?" he finally asked, just glancing Spider-Man's way as if it was an afterthought. Immediately and physically, or dealing with the shit Smythe and half of the city seemed to like to throw at him, Tony would accept either answer.