Tony's trouble- alright, part of Tony's trouble- is that he always has to have the last word.
It's gotten him into more messes than he can count, over the years. From the mundane- sullen silences over the rare family dinners, Stane looking at him with what he thought at the time was disappointment but he sees now was probably more akin to disgust- to the dramatic, Tony's mouth has gotten him into far more danger than it's ever gotten him out of.
It's brought him here, to the cell on the Helicarrier where Loki sits, gagged, awaiting transfer to Asgard.
"Told you." It's not much of an opener, but it has the advantage of being true. "The next time a genius tells you something, you might want to listen."
Loki regards him coldly, hands still in his lap. He looks uncomfortably like an animal- muzzled, caged, but still dangerous.
Tony's always had a complicated relationship with dangerous.
"I don't know if this is going to get through the crazy, but you're lucky to have Thor. Me? If you were my brother? I'd have killed you."
Loki doesn't even blink. Tony can't actually remember ever seeming him blink. Not that he was looking. Instead, Loki looks Stark up, down, and shrugs. Spreads his hands.
Indicates Tony, then himself.
It takes a second for Tony to realise what Loki's trying to say. It is, after all, what Tony himself realised a few days ago, back on the Helicarrier. Loki is a madman. A psychopath. A killer with daddy issues who wants the world to kneel in front of him because then, finally, he might be able to fill that empty hole inside. There is a gnawing void at the heart of Loki, a wasteland only barely covered by his bravado.
Loki is saying that he and Tony are, fundamentally, alike.
It takes him less time to decide to deliberately misunderstand this.
"Sorry?" he holds up a hand to his ear, exaggerating. "I can't..."
Loki rolls his eyes. It's far too familiar for such a menacing face- and as such more disconcerting than all the glowering and glaring.
"Enjoy your return home." Tony turns to leave. "You don't deserve it."
Loki shrugs. How much do either of them deserve anything they have received?
And Tony lets it go, and for once in his life lets someone else have the last word.