I certainly agree that working this hard is not healthy as a rule.

They can definitely hire staff, especially in the US of all places there is no shortage of promising engineers. Very few people get hired to these kinds of plants fully trained, most pick up 90% of their skills on the job. It's just a long process. The real reason, at least for our plant (a plant that has already returned all its investment dividends tenfold, passed its calculated lifespan, and is now just a money printing machine), is that there are chiefly 2 ways (3 in our country, but this isn't about that) that the plant becomes more economical to keep running: process improvements or reduction of labour costs. The sacrifice first comes for maintenance staff, overworking them, then for all other disciplines depending on whats allowed to be gutted by law. Engineers are actually making out in a relatively "favourable" position, since they can directly contribute to process improvements - the company has fewer incentives to let them go. This situation ends in there being a settled number of so-and-so engineers, which is "understaffed" according to your and mine definitions, but is the perfect amount for the line-go-up number-crunchers.

Being an hour and a half away actually makes it make even more sense theyd sleep there to avoid a commute.

My guess is the top right building is housing. You have 2 gate houses, one just to the main building and one to that side building. Would make sense if researchers were living in that side building that there would be visitors or maybe even family living with them there that they would want the extra gate for. Since they wouldnt be allowed inside the main building.