@Ed oh I see, you’ve already added Naked in a lift: With the doors CLOSED! Most lifts have mirrors in them so it’s easier to take a selfie.
That’s actually pretty easy. I thought it was going to have to be a video of you taking the lift down, leaving it and then taking the stairs back up again. But with the doors closed, it’s not really that much different from being naked in a changing room unless you chose a particularly packed lift (elevator) to take your photo in!