Just encountered a weird bug, or at least we're pretty sure it's a bug. We were on the 16th floor, Deconstruction Zone: Cold Storage, and found ourselves at a gate we couldn't open. There were no other enemies on the map, and we'd destroyed every box as well. No switches or alternate paths. Our entrance elevator was on the left, and on the right was the exit elevator. The only way to open the gate, as far as we could see, was a button on the other end that we had no way to get to.

Here's a picture of where we were at.

Thanks!