[I wonder if anyone thought about how much this should hurt him. That arc reactor is bolted into his rib cage with has had considerable amounts of bone removed which should be there. There is at least a four inch deep (because Pepper managed to put her whole hand inside) cylinder of metal in his chest roughly 3-4 inches in diameter.
That isn’t a light love tap there. You can tell from how it moves at contact. Loki doesn’t need Tony, not really. He’s already gotten pretty damn far in his plot. He just needs to stall a bit. He doesn’t care if Tony dies. He pressed the tip of the spear a lot more carefully to Clint.
The second his eyes fly open at first, I think he experiences a wave of pain and then pushes it the fuck back. You go, Mr. Stark.
Most of us would probably have dropped to our knees. Not this man. He’s had to live with the arc reactor in his chest for how many years now? Imagine waking up in the night in agony because you rolled over onto your stomach and a hunk of metal is constricting some main arteries. He only flinched slightly because he’s been through so much worse.