Killian manages to cut off Iron Man's leg but when Stark emerges from the suit he is physically fine. Why wasn't his leg missing?
In the end fight, it does show (in slow motion) Tony ejecting his leg from the right Iron Man leg right before Killian chops it with his hand. But I'm pretty sure that the leg doesn't actually attach that way. Doesn't it work more like a sheath and not a greave?
you can't really see it because it gets out of the frame very quickly but the leg does come out and then it cuts to the shot with his leg showing without the armor. marvel aint that stupid