This was it. The big moment, the final hurrah. Tony grit his teeth as he and Jarvis pushed the suit to its limits for the turn, barely managing to turn the missile in time before it hit Stark Tower. The scraping of the Iron Man chest piece on the wall of his own building being one of the only things between it and a full nuclear strike was unnerving on a level he'd never be able to express in words. But then they were clear of it, and there was nothing ahead but the portal into space.
He braced himself, not able to look at the picture of Pepper that displayed as Jarvis tried to reach her. There was no time to say anything now anyway, and he was worried that looking at her would make his ability to send himself on a suicide mission obsolete. He was really quite selfish, after all, and these aliens were ugly enough to be running towards without a picture of his girl making him want to stay.
The passing through the portal was immediate and almost anti-climatic, but the wave of relief that he'd gotten the nuke through and aimed towards the ship before it went off was quite pleasant. It was just too bad that the natural high was dampened as the power of his suit ran out. He blinked as the power went out, then grunted softly as it started to draw power from core keeping him alive. Jarvis was supposed to prevent that from happening, but he was out of the computer's control here in the middle of space.
He stared out into the alien landscape, at the explosion brought on by the nuke, then closed his eyes. It was over, all over. But the Avengers would close the portal and defeat any remaining Chitauri, and hey, Manhattan wasn't nuked. That was something. It was quite impressive, actually.
They'd let Pepper know he'd done that, and maybe she'd be impressed too. She wasn't often by him anymore, she'd known him too long and had taken care of too many of his messes. He had no doubt that the rest of the world would recognize his amazing sacrifice, but he was always less certain about his girlfriend. He figured she'd be happy, though, if she didn't try to leave him again for making her worry about his life. Or, to be more accurate, if she didn't curse his memory for actually getting himself killed.
As his consciousness slipped out a smile almost tugged at his lips, thinking about how mad she'd be this time. And then there was no thought at all, or feeling.
The Iron Man fell through the portal just as it closed, but never re-entered Manhattan's airspace. Instead it tumbled, lifeless, striking an old building and puncturing a hole through the ceiling and two floors before making an impact in the ground just inside the walls of dieFestung. Tony never knew he made it back through the portal, much less that the portal hadn't taken him home.