There's a location where you must crawl through a vent to flip a power switch and then crawl back through the same vent because there's no other exit from the room with the power switch. To get into the vent, you climb onto a table and ope n the vent door. Then if you just move forward, you'll crouch and climb into the vent. Once you're through, you drop onto a ledge and flip the power switch. However, when you turn around, I can't get back through the vent. Simply moving towards it doesn't work. Neither does jumping or crouching or crouching and jumping. I've also tried moving to the back wall and running and jumping. I am stuck. I've tried a mod called Freecam and Teleport but it doesn't work for me. Any suggestions?