If he does try something, I think it'll be this Friday. Because "Saturday Night Massacre" is already taken (ha. ha.). W̶e̶'̶r̶e̶ ̶i̶n̶ ̶t̶h̶e̶ ̶m̶i̶d̶d̶l̶e̶ ̶o̶f̶ ̶a̶ ̶C̶o̶n̶g̶r̶e̶s̶s̶i̶o̶n̶a̶l̶ ̶r̶e̶c̶e̶s̶s̶,̶ ̶a̶l̶t̶h̶o̶u̶g̶h̶ the Senate is still in session attempting to get Trump nominees confirmed into their positions. We already know he wanted to fire Mueller last June, and the story just broke tonight that he wanted to do it in December. This Cohen raid is arguably a wayyyyyy bigger deal than some subpoenas.
I find much solace in the fact that even if Mueller is dismissed tomorrow, there's no legal avenue for Trump to halt the investigation into Cohen's records, or pardon anyone found guilty (state-level investigation). Brilliant move by Mueller. I think it's also likely Mueller feels like he has a decent obstruction of justice case built at this point, along with substantial amounts of dirt on plenty of other little fish.
God, I sound positively conspiratorial, I know, and all I'm really doing is assembling the past year's worth of stories from extremely reputable news sources.
Edit: I was looking at the 2017 calendar, like an idiot. I apologize, here is the 2018 Congressional Calendar, Congress is not in recess this week. The next lengthy recess is not until August.