Excuse my ignorance here, does the timer just keep the turbo spinning?

Or is your engine running.

If the latter then you committ an offence of quitting,(I assume that there will be no one in your car ).

BUT, there is a stated case where a distance is mentioned, ie, how far from the car the driver is 'allowed' to be. Damned if I can remember it though.

Of course, if you leave your car on private land(your driveway), then no worries at all.