Security turn over rate

Not something we've ever really discussed. But I'll give you a guess...

It's going to vary. Some of them are going to see it as a relatively cushy gig. After all, these guys are mostly military vets and a lot of them were special forces of some type or another. Doing patrols and providing general security on an isolated, well hidden facility is extremely low adrenaline for them. So the real extreme living on the edge types won't stay long. Some of the others will see the kids as powder kegs and not be able to handle the lack of control kept on the explosives. Those ones will put in their minimum couple years to get a good reference and network some before leaving. On the other hand, they DO see enough action and have to deal with potential problems with powered teens, that the sloppy and not so bright ones won't last long.

There's also a limited number of opportunities to 'move up'.

On the other hand, Whateley pays well and there are always opportunities for highly trained security in the corporate world and making that transition after putting aside money and building a network of supers that know you... could be very profitable. Even if you don't end up working as for one of them. Which is also a possible outcome... on both sides of the hero/villain equation.