That was the point Tony was making, so he was ready to talk over Steve, "Yeah, you left, he stayed right there, you're the object in motion," but it didn't seem like they understood it the same way and as Steve continued, Tony bit his tongue peevishly. It wasn't an important enough philosophical difference to continue the argument when he couldn't then keep ignoring, "Something else came up." 'Like it always does', Steve had said, but that part didn't sound true now. Steve betraying his trust would be better described as 'never', and Tony held his gaze with a flinty challenge, daring him to try to rationalize that thought out loud.