Extend the Story - Add a Room

You get to the stairs, with nothing trailing behind you... Thankfully. As you are marching up the stairs, you trip... You fall back to ground level, being thankful you only made it three steps up. You get up, and finish conquering the flight of stairs. You get to the top, and there are three rooms. You need to find a phone, so you know you ought to open one of the doors. You...

Try the second door...