They hotfixed it and it doesn’t work anymore. Your character remains logged at the location you petri and you’ll die when it wears off.
Now if you want a reliable exit from a dungeon/raid you carry 2x petri and refresh it after leaving group with <60s at a good time. Or leave group and wait to petri until <60s on timer (but that requires ~10s after leaving group before the timer starts, so it doesn’t work well in many situations when you’re doing a snap petri to save your life, particularly for tanks.
Big difference now though is that you can’t effectively petri in the overworld, whereas you could before with alt-f4 because it would reset mob aggro when your character logged out and/or you could use unstuck after alt-f4 to remove your character from the situation.