Vampire genetics?

[It is his best guess. In truth, Alucard didn't actually expect Gideon to keep herself upright. A half step is pretty damn good all things considered, and it takes actual restraint from Alucard to not knock his shoulder against hers just to be a dick. Still, he has to shout all of this, and make sure none of it comes off as condescending. It is a rather tall order.]

You didn't fall over and you didn't move that far. Against anyone else you'd have been fine!