Hide in plain sight: Tele to varrock
The guards won't spawn untill you move or get attacked, and nobody can attack you because they're all in the safezone.
It's a bulletproof method!
Seriously though, there are two reasons this might not work: you have to move every once in a while for your skull to go down, and guards could already be in varrock center and could attack you. If you have 30 seconds left on your skull and the guards aren't around, this would probably work and would be very funny to see