Instinctively, Tony was calculating; the distance, speed, mounting momentum and the rapidly lessening seconds he had to react, but he was grinning, holding his breath against the whipping wind, the cold not even registering anymore. That was, until he twisted out of his dive to slow his fall, and caught the reflection in the windows above him. He didn't have the breath to curse, just struggle in midair, trying to right himself even as his t-shirt and jeans started to melt away. The second his palms began to glow he forced a thrust of energy, which made him flail, uncontrolled without the familiar resistance of the Iron Man, tumbling in the air until Steve fell into him and Tony flung his arms around him. The breath he held was slammed out of his chest with a bruising impact and they hurtled together towards the concrete with flares of light from Tony's boots glinting off the glass facade of the Tower.
In a dangerously deep arc, they pulled out of their steep fall, swinging around Stark Tower until they were righted and Iron Man was hovering. The last of his red skin was still spreading across his heaving chest, liquid to unforgiving metal, and he clutched Steve with gold fingers digging into his sides and hard planes cutting into his skin, Tony's anxious, perplexed and mostly shocked glare obscured by his faceplate.