You cannot open a cylinder lock with a key inserted from the inside. The key only works from the outside to unlock the door.
Use a siphon hose inserted into the tank. To get the remaining fuel out or if your vehicle has an anti siphon device you will have to disconnect a fuel line and turn on the key. This will activate the fuel pump and fuel will flow from the line.
Could be the key was inserted up side down or it was the wrong key for that vehicle.
a tab is inserted
After you've inserted the key, spin the cylinder counterclockwise until you can open the front.
The bulb is blown or has been removed. Replace the bulb.
Sharps and Flats
the key switch in the steering column has gone bad and has a part inside of it that is probably broke.
It means you put the key in the lock. The plug is the name of the part of a lock cylinder that turns when you turn the key.
check
get the key and insert said key to ignition, once inserted turn ignition to the right and BAMM your on your way.
With the key inserted into the lock.