Because I like to try and lipread and this jumped into my head. Serious apologies for the punctuation, but I'm going to blame that on the asphyxiation going on. Dialogue taken from the movie.
"I've got a nuke coming in, it's gonna blow in less than a minute."
Time has a funny habit of seeming to flow variably. Ask a child who's waiting for Santa, a student waiting for the bell to ring, ask a parent watching their infant fight for breath or a couple sharing their first perfect kiss; time seems to warp, usually in whichever direction you don't want it to.
Radio in his ear, JARVIS making suggestions and he's counting down, seven, six, and flying up and there's stars and
Breathing, he can't breathe and at first it's the glory of space and overwhelming fear of impending invasion and he almost doesn't think about the suit shutting down and the utter, utter silence, and the back of his mind telling him just how little time he has before he runs out of air five, four,
And gravity from the portal somehow and wow physics just took a kick in the pants and beauty and terror and pain and sorrow overwhelm him even as the ships in view seem to retreat, as he falls through space back towards the uncaring earth (Oh no not again whispers a fleeting, hysterical voice from his younger days) and three, two
And his eyes close against the explosion and he hopes that this, at least, has accomplished what he planned and his team and his few friends will live and this is so much more of a legacy to leave behind
One.