My last job had the same issue with stair exits--you could (and many of us did) take the stairs down, and exit into the lobby, but IIRC, you couldn't get back into the stairwell from the lobby. And taking the elevator to the 2nd floor just so you could hop out, badge through the door, and go over to the stairwell to walk up the next two floors was impractical.
At my job now, I'm on the 2nd floor, and there is no elevator :)