We did ! It was a fun little extra! Wouldn't call it anything spectacular compared to some of the haunts we go too, but it was fun! But to answer your question I don't think you HAVE to go through it in order to get to the show.
So we actually didn't buy anything at the concessions inside the tent, so unfortunately cannot %100 answer that... One thing for sure though, it was an amazing show and such a fun night, you'll have an absolute blast!