key spawn chance

[Reckoning]

is there a pattern to key spawns for certain floors?
I know that in order to get a floor's key, you have to atleast be on that floor itself.
But, is there a smaller chance of getting a key the further out you go? Because it seems most of the floor keys I obtain are close to where i spawn into the floor

[AP STP]

The keys are completely based on RNG and can be very rare depending on your luck. It took me a super long time to get keys in some levels while some took less time.

[Raime]

how do i get the lvl 23 key? there's no boxes and no survivors to trade on