Behind the door there is nothing but a second door and a holoscanner. It stands to reason that whoever owns this club would want to keep track of who goes in and out. But, once you scan, it would be very difficult to deny you've been here, if it ever comes to that.
You hold your holo against the scanner briefly and it blinks from red to green. The second door opens, revealing a flight of stairs going down. You can hear the dull thud of a beat coming from another heavy door at the bottom.
Descend