As someone who wants to get into Master's racing, I likewise am trying to figure out how to "scratch that itch" and still be able to show up to work not in pain, both physically and financially.
As Calsun suggests, road racing and TTs feel like better disciplines to me. Even the best, highest level criteriums have regular crashes. I can only imagine how ridiculous it can be at Cat5 level where people are both fit and inexperienced.
I've been fortunate enough that my town's bike fitter was a criterium guy before his knees gave out, and he has a lot of great advice on how to stay safe in races. His advice: a) try to get into the breakaway early, as the fewer riders you have around you and are working with, the safer it is; b) don't sign up for races where the finish line is at the end of a descent; c) the more damage you can do to the peloton, the safer it becomes for everyone, as this will stretch the peloton out. A sprint against 5 people is way safer than a sprint against 20 people at the end.