Father Raquer was proven correct when the drones captured the overall movement of the sea of fog that had appeared out of nowhere. Even with the dying light of dusk, it was clear that the fog was moving in the direction opposite to theirs, very quickly at that, too. If they had chosen to turn the bus around to make a run for the entry station, they'd have ended up reaching there alongside the Blightmist, provided that something disastrous didn't happen to the bus during the journey.
Hoping for such a scenario was mere naivety. Even Mir, who had only ever witnessed Blightmist descents from afar, knew that the chances of being safe for so long inside one were slim. Not many people had survived these things, and all of those who had survived had one thing in common—they'd rushed away from the fog at the fastest possible speed.