Great Question! I would say, IMO that the engine will not shut off until the gas is depleted. (These engines do not not have cylinder de-activation. A good thing IMO.) They have the electric fans on the radiator that turn on to lower the water temp for such an event. There are times when idling times could be long....traffic delays etc. I doubt you can lock yourself out of the vehicle w/the the key in the ignition with or without the engine running. (Maybe w/another transmitter key?) You'd have to work on it. But another key/magnetic lock box, have it programmed @ lock dealer and hide it somewhere on the underside. (Just in case you lose the key.) Have not seen this in the owner's manual as well.