This will most likely work, just MAKE SURE it's pointed in a safe direction. Wouldn't be too hard to set off the round with the tip of a screwdriver.
I haven't watched the vid. But I was attempting to remove the rear plate as @biker_bill suggested in an earlier post last night when I decided to try and pry between the chamber and frame from inside the mag well with a large flat blade screwdriver. The slide actually moved a little towards the rear so I kept prying andthe slide finally moved enough for the cartridge to drop free. I am headed to Glock this afternoon to let them take a look at it. I have not tried to chamber a round but the slide functions and moves freeley and locks back on the slide lock with an empty mag.