that's okay! I wasn't planning on using him as a combat obstacle either, but the statblock got me thinking about why he would send the party down there and I could only think of him wanting them to be monster food, and I couldn't imagine a compelling argument for him running away with the ability to use death rays and the like.
that said, I enjoyed the thought experiment of a very strong wizard passing himself off as a weak one to lure adventures downstairs as meat for his experiment, and the doom that would come in their minds if the experiment tells them that they've been tricked and the guy upstairs is too strong for them to handle!