Tson
The party advances along the road. The wall is visible and slightly lags behind the party on the road, and everyone wonders how it passed through the mountain. As they walk for enough time for Adams to start complaining, a peculiar object starts approaching by the road, which is now made out of asphalt again. The party stops to see it properly, and sticks to the barrier.
...
The object comes closer and it appears to be a giant banana on wheels... no, on tank treads. The banana is facing both ends upwards, and the thicker end bears a crude turret. The middle has a small hatch, from which a bald, pale man is looking around. Two other men are literally running on tank treads, and judging by the tank's occasional veering to the right where a slightly more chubby man with long hair is running, the tank is powered only by these two men running on the treads. The chubby man is silently singing something to himself. The bald man is stomping on the tracks so hard it sounds just like drumming, and in a catchy rhythm too. On the backside of the tank, a vampire-looking man is hanging and shanking the banana with a keychain, trying to eat it. The other end of the banana has a flag, on which a long-haired man is hanging, and apparently fiddling with the flag, as if trying to use it as a guitar. The fifth man with a similar haircut is looking out from the hatch. He greets the party, and hits the brakes, causing both runners to fall off the banana tank. They both complain and stand up. All five are pale, skinny except for one runner and look extremely grim.
"Hey! You don't seem to have any FTL fuel here, do you? We could drive this thing offroad if we get some fuel to power it. Or blood, because thanks to an invention of a man in a grey suit, many tanks now drive on blood. So if you'd like to sacri- ahem, volunteer one of you, we could hold this barrier open, and the wall too if you'd like to revisit stuff."
[Locked option: requires at least 10 FTL fuel found]
[Inform them about the upcoming mountain]
[Offer an item to them in exchange for opening the barrier]
[Ask what the hell is up with clothes and the banana tank]
[Sacrifice a party member, but not their gear in exchange for opening the barrier and roadwall]
[Leave them be]