It would highly depend on the type of situation in which we were breaching this room, if it was a hostage situation, a no-knock warrant or an unknown trouble call. I will assume there are armed suspects somewhere in the building regardless.

Team Leader would retreat - knowing that I was unable to position the camera properly to scan the entire room.

Breacher up, breach the door - deploy a flash-bang "grenade", left and right stacks move in tandem into the room - team one (left-side) would immediately cover the "unknown room door" at the same time team two (right-side) would be covering the staircase down.

The reason for this is that Team 1 would immediately have view of the unknown room door and Team 2 would have immediate view to cover the stairwell.

The rest of the room will be cleared in a pivot motion (though it should be clear as there was a clear line of sight with the snake-cam). The stairwell serves as a bottleneck, one operative should be able to hold the stairwell with a reasonable amount of cover - the remainder of the team would breach and clear the unknown room, and then breach and clear the room(s) downstairs.