It takes a few moments for thoughts to catch up with the rest of him, that there is no emergency and no spell and no need to call for help and nothing Lucius actually need do at all on account of the fact that the woman is quite dead. He's seen and been around quite a lot of it, some at his hand, in front of him, standing beside him, and as the bodycount of relevant people ticks up by one, he feels the loss a little bit like something more chipped away from something else that was already eroded and jagged edged.

It's a pity, really. He quite--

And then she's breathing. Noisy, like the drowning.

Caught between deep revulsion and surprise, and more amicable concern that should have him rushing to help her, Lucius simply stops and takes a step back, and soon enough, points his wand at her in instant suspicion and disgust. It seems relatively likely that something ungodly might be puppeting the broken body of a dead woman - he's certainly seen worse in the thickest parts of the fog.

Of course, he isn't about to avada kedavra it right away, and he'd like that to be an intellectual need to know what it is he's killing. In truth, he's just not wholly convinced he still isn't looking at Vanessza.