everyone come talk to meee
There was probably a good reason for Steve's weird behaviour. If Tony took the time to think on it, he might have come up with 'surprise belated birthday party', considering all of the facts. Unfortunately, Tony didn't take a lot of time to ruminate on the biggest of decisions, and most of his solutions involved the Iron Man. It was reliable, malleable, they understood each other. This probably wasn't the best application.
He burst through the doors onto the roof with both hands raised, palms glowing and red gleam of the armor disappearing up his shirtsleeves and spreading up his neck. It took him a beat to adjust to reality, accepting that the bodies invading his space were not a threat to him, but there was a distinct lag as he scanned the crowd before he smiled even after he dropped his hands, brow knit and searching. No Nick, huh? That was okay, fugitive, known allies and all that. He blinked, shook it off and made up for lost time with a bright flash of a flawless smile, non-threatening hands turned out in surrender. "Wow, tense. Am I interrupting something?" he accused now that the heavy weaponry was out of sight.