Killed everyone in this small warehouse building, need to get upstairs but when get to open elevator doors, it is like a wall to me. I can't get in. There are no buttons, I am not carrying any unusual weapons, everyone on my floor of the building is dead. Why can't I get in. I stood in front of the open door pressing x for a while. Nothing. Help! Can't get any further if i can't get upstairs.

The gate should be already open and you should walk in and it will automatically go up.

The gate is already open. But when I try to walk in i bounce right off the open space. I can see into the elevator, but can't walk into it, it's like it has a glass wall in front of it.