I'm trying to go visit Mr. Freeze for the first time and I can't figure out how to get past this door. I shoot it with my electric gun, but it only opens the door about 8 inches or so. I've tried "rocking" it up and down (does nothing), finding a way to shoot it from behind (no open gap), shooting the nearby camera (maybe someone would come out from inside...but no) and using my remote Batarang (can't find anything to hit inside) to no avail.
Am I supposed to go through this door? I can't find anywhere else to get in.