Considering The Last Stand is basically Death Toll but elsewhere, I imagine this version of The Last Stand taking place in a alternate version of Dark Carnival where they stole a Truck from the parking lot of the Whispering Oaks instead of going into the park.

Death Toll and Dark Carnival are both the third map of the campaign, so this could support the headcanon. But I understand it doesn't make sense but it's fun to imagine.