There is this ATC recording where an A340 pilot requests to leave the aircraft and close the fuel panel on the bottom of the fuselage, while the aircraft is on a taxiway (the request is made at 2:50). Now, here is a picture to show how to get in and out of an A340 without deploying the emergency slides and causing even more issues:
(Source: http://www.flugzeugbilder.de/show.php?id=695499 and yes, I realize this is technically a A330)
However, the picture also makes it look like it not actually possible for anyone to reach the fuselage from the ground. Is that actually the case? And if so, how would the pilot actually reach the fuselage and close the fuel panel?