Sorry, bud - natch. The only way to "decock" a Glock is to pull the trigger.
And the gun isn't truly considered "unloaded" until the striker is released.
Yep. This was the procedure we followed in Bosnia. Drop the mag, charge the weapon three times, inspect chamber, point in a safe direction (into clearing barrel for example) and pull trigger.
What's funny is- people still screwed that up every once in a while. How? Don't ask me, but there's always some dim bulb that will dick up the safest "safing" procedure.