Rob Siminoski has been in the theater, in one way or another, since he graduated from college. But after 10 years at the Universal Studios theme park in California, he is only No. 13 on the stage-managing roster. Even if the park, closed since March, reopens some attractions — the WaterWorld stunt show, say, or the Nighttime Lights at Hogwarts Castle — he is unlikely to be among the first to get the call.His luck is that his union, the International Brotherhood of Electrical Workers, offers an apprenticeship program for on-set movie electricians. It takes five years, and Mr. Siminoski, 33, is going to …
