'Course, William wasn't idle. He had already tensed up with her words- "get out of the way" sort of thing to the person standing between himself and the old-as-hell psychopathic murderer- or at least, he assumed- and had already begun edging both his hands out of his pockets to take defense or run.

So when she darted towards him, it was more reflex and surprise that made him stumble backwards, inadvertently dodging her pale hand. Landing on his back with an [i]umph![/i], his pepper canister dropped from his hand, just out of his pocket. 

So then he grabbed it, raised it up, and aimed it right at the elder vampire, more likely to start doing something to him... and sprayed the entirely modern-ish spice liquid seasoning stuff at her. He didn't care where it hit, since the smell alone made his eyes irritated and start watering immediately, his nose burning with enhanced senses that he most certainly did not have beforehand.