Kalinda swallowed, looking up when Zack returned, "I have no idea what I'm doing" She said softly, truthfully, "But I have to do something, right?" She examined the arc reactor. She had no idea what frost had done, but...

that was the strange thing about humanity. Even when you didn't know what to do, you still tried. And She had, somewhat clumsily and probably poorly helped when fixing the suit before. So she could try, at the very least. She figured out, quickly, shifting so Zack could contnue with the chest compressions, how to replace the arc reactor, but her fingers were shaking, and she had to stop a minute. 

[i]take a deep breath[/i] she told herself, and she did so, continuing with what she was doing. When she was finished, she leaned back, biting her lip, hardly daring to breath.