Enter the Fuel Dump fortress by hopping on the "phone booth". Result: it doesn't work! Comments of the author (Richard): "HAHA Ça marche chu sûr c'est vous autres qui n'etes pas assez bons!"
Finish Oasis in 2 minutes by using a covert ops and an engineer: go through the door (without the axis noticing, of course). Verdict: it works! (must be lucky). Comments of the author (Redge): "Ça va marcher."