when you have enough fuel in jet pack do this:
*fire jet pack
*while holding down jet button press esc.
*with the ESc menu onscreen, release jet pack button
*watch as your jet fuel runs empty ^even though game is paused and u released key^
*return to game
*you should have the speed as if you emptied your jet-pack, but ur still on same location.
It works when I play gainst bots.

why can the jet fuel change when the game is paused, but if you reload, the reload dosnt finish when paused?

bug is known :D ive told michal about this about 2 months ago.. but it seems that he
hasnt fixed it yet... also not in 1.2.1

because of the way the game was made maybe? there are lots of other bugs, and one like that really isn't too important because it only affects a bot game, or maybe a game host?