Sounds somewhat like what the planned with the drone but subsequently dropped before the game entered beta.
A player could jump in on a mobile device as a 5th member acting as a drone giving guidance/bits of support.
Did wonder if something like that had been intended from the odds left over stuff you find around the map, etc. and/or partial menu functionality, etc.
damage through walls, NPCs meleeing me and doing not damage or 1 hit meleeing me from the other side of the room, health completely random visually to what it actually is, completely random length skill cooldown times, etc. etc.
She wishes she could get out there and help...