Guide to Sixth Ending
How-To
First of all you had to talk with Vallery, you need to get the basemant key and the large old key.
After the talk Vallery will ask you to open the coffin. Take the hammer from the table next to the tape recorder at the basemant desk and hit the second basemant doors safety lock.
After that go to the main hall of the mortuary and get the fuse from the desk right last drawer.
Go to the bathroom, open the fuse box and use the fuse. Go back to the basemant open the second door and pick up the bolt cutter.
Try to cut the lock, take Vallerys mark and burn the right possessed body with this mark. If you did everythink right after the burn the game will continue.
Go back to Vallery cut the lock, and the cutscene will start.
You forgot to mention sliding the thing on the second basement door’s lock