'Fast Getaway' Cars = Big Plot Hole?

The two E-type Jaguars and Aston Martin are there in "the event something goes wrong and we need to make a fast getaway". But, exactly, how was this to take place? I guess it was to be able to quickly spirit out the Minis' occupants, but there are six people in the Minis. Since the emergency cars only hold two people per car, and they'll all have drivers, what about the extra three guys?

It was quite dramatic and fun to watch the Lamborghini Miura get tossed over at the beginning, and I suppose someone thought they'd have to use equivalent British exotic sports cars to be tossed over in a similar fashion later. But it's not very realistic to use the sports cars as back-ups. They could have easily used Jaguar sedans (or 'saloons' as they're properly known). They could have held all of the Mini occupants, and even taken on board the gold. They would also have been nearly as 'exotic', when tossed over the side, as well.

Frankly, they should have just used three more Minis or, better still, Fiat 500 Abarth cars (particularly since Fiat was so willing to supply vehicles for the movie).