There are two safes in the RPD--one in the West Office and the other in the Waiting Room. Both yield valuable resources well worth grabbing. We won't spoil what's inside each here (spoiler: they're all useful items), but we will reveal how to open them. The safe solutions are found in memos scattered around the building, which we've detailed the locations of for all of you completionists out there.
Bank size: It does not necessarily refer to the total number of compartments, but rather the number of compartments wide the entire cabinet is. So a bank of three may contain six lockers, for example, if they are two-tier lockers. In short, the total number of lockers is the bank size multiplied by the number of tiers. Sometimes the term "bay" is used instead of "bank", although "bank" appears to be the more standard term; on other occasions, "bay" refers to a single locker width within a bank, including all tiers of locker directly on top of each other.
Clean/dirty lockers normally have two or three parts within the locker. One part is meant for dirty or clothes that are worn, and the other side for clean clothes. These lockers are meant for hospitals or other medical workplaces where it is useful to keep work and personal clothes apart to reduce the risk of infection. These lockers are also useful for factories where work clothes can become dirty and it can be very useful to keep them apart from personal clothes.