Even over the sounds of yelling and swording all around them, Wilson manages to pick out what Klaus said, and that plus the realisation that he recognises this guy is enough that he whiffs the blow. Klaus wandered into the Constant once, somehow, and said hello to Wilson and Webber and Chester before vanishing again. He didn't know they were married. What is he doing?

"Give me the sword, then!" Wilson waves his arms in frustration, then stows the ham bat out of sight and grabs for Klaus's weapon. "I wanted you to stab me!"