Originally Posted by
eternaltransit
You can, if you ask the driver - I once did that as I was sending some people off just after my arrival at LHR.
I tipped the driver some extra cash for the inconvenience.
Likewise - I did this when arriving on QF and needed to take a quick shower in the AA arrivals lounge. Tipped extra for the delay.
As long as you're talking more of a quick shower than a 2hr stay, the drivers will most likely be fine with it.