The metal holder that the window resides in is a snug fit...but not glued on or anything, so if you can get the regulator to move the window down any, you can push the window back up and out of the metal track. This will give you the necessary room to move the regulator out of the door panel bolt slots and completely remove the assembly out of the door.
It is otherwise difficult to perform this operation with the window (and regulator assembly) in the fully closed position...there is no room for movement. If ou plan to replace the regulator anyway, you may try cutting the cable...just beware that the weight of the window will now slide down the track rapidly, so make sure you anchor it somehow, or you will have to deal with a broken window too.
BTW, watch out for all the sharp edges...you may have noticed that there are lots of them. I have a few battle scars from that DIY job too.
Hope this helps.
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car