There is an element of luck to accessing the Paramo secret rooms, as it requires you to loot a key which can be used to open one secret room door. The issue is, these keys are randomly dispersed, meaning you have to play like normal, looting and scavenging until you find one.

It's also possible to go several matches without ever finding one though, so it really comes down to the luck of the draw for who can access these loot-filled rooms.