Tell us about yourself!
This is extremely dangerous idea as you will likely suck fuel fumes into the vacuum cleaner (I haven't seen any domestic or shop vacs with brushless motors yet so they will have sparks) that will ignite and set the vacuum cleaner on fire and then possibly your car. It is a 4 stoke engine after all so one of the cylinder at least will be on the compression stroke when the engine stopped (post fuel injection but pre ignition). There will also be some combustible blow-by gas in the crank case that will be drawn out by the vacuum. If there is some other undiagnosed issue such as a dribbling injector (or leaking carburettor) the risk is even greater. You'll get away with it 80% of the time but the other 20% of the times will end catastrophically and may even get you a Darwin Award.