Tony has been in the park for most of the day, but it's a decently sized thing and he was in mostly one spot. So when he happens by a very familiar, hulking figure, he freezes, peripheral vision trained on Steve. Does he keep walking? Does he ask him what the fuck he's doing? Because just like Tony, he appeared to be up to something.
"Captain," it's a plain greeting, trying to hide the hurt in his eyes as he passes.