Hidden exit

There is a movie festival going on in town and I am at the Bethesda Row theater after the screening of "Roots" a weird Russian film that was advertised as a comedy but features a rape scene that ends up with the woman asking for more. Very funny indeed.
Instead of heading out directly I chat with one guy I know and who happens to be one of the volunteers of the festival. He wants to show me the place where they put all their material . A door and a small corridor where I see a table and a couple of chairs, folded. As I step in, the door closes behind me and we're locked in.
The volunteer, who must have had this happen to him quite a few time, tells me that we should exit from the "other side". I'm not quite sure what he means but I follow. We walk through one door, then climb stairs and finally another door that opens on a nicely decorated lobby. We've crossed one block underground. We are in a building's entrance located in the street nearby.
The door on this side is hidden, disguised as one of the wood-looking panels that cover one side of the lobby. The door closes silently and locks itself into place. Now the entrance is quite invisible. For a minute I felt like James Bond.