You'll want to grab shcherba's keycard first, since that opens up all the good spots. The control room's probably your best bet to start - there's this sweet suppressor blueprint in there plus some psi-blocks which trust me, you'll need with that controller lurking around. The research lab downstairs has some decent scientific gear and meds, just watch out for the flesh rats down there they can mess you up if you're not careful. Something interesting about the generator room, there's usually some military stuff near the actual generator, and if you're brave enough to deal with the electric anomaly, there's more goodies past that including dvupalov's notes which you might need later.

Maybe worth mentioning that the spiral staircase area has some hidden stashes, just keep an eye out behind stuff you can move around. Quick word of advice - bring plenty of bolts for those electrical anomalies, and definitely pack some psi protection before heading in, that controller is no joke. Stuff tends to be better behind locked doors or past the dangerous areas, so come prepared with meds, but the payoff is usually worth it. And yeah, saving often is your friend especially when exploring new rooms - nothing worse than losing a good haul because of a surprise zombie ambush.