Driving without the key??

[evo]

Hey guys

I often leave my car with valet's (car jockeys) and the other day forgot to hand them my audi a8 key - they got a little up the road before i realised they had not got the key and i ran up to the car and handed it to them...

they said they'd not realised but now they look at the screen it did say key not found or something...

my question is... after initially starting the engine with the key in the car... how far can you then drive the car without the key in it before it shuts off? or does it not shut off?!

can't find no mention in the manual...