That sounded like an accusation to Tony. What were the Avengers now without Captain America, anyway? A war monger and his liberated terrorists. If they would even have him anymore. Perhaps it was Tony that should have been stepping down, but even if he had to systematically plow through the whole superhuman community of North America to keep a working roster under his leadership, he couldn't trust anyone else to take control. Tony knew what needed to be done, and knew how to do it, even if Steve doubted his ability.
With another deep breath, Tony gained more distance, and instead of wondering aloud where Steve was leaving to or thanking him for everything he had done or downright begging him to reconsider, Tony just said, "I hope you don't plan on getting in our way." It wasn't quite a challenge, but flat and purposefully steady, Tony's brow knit with determination. He wasn't going to break in front of Steve.