Godzilla survival oneshot

I'm thinking of doing a one shot set in a city being attacked by a Tarrasque. The party would play a group of survivers in the city who would be trying to escape without being killed. They would obviously be unable to kill it so the game would be more cloverfield than attack on titan with the players having to do more skill based challenges to avoid dying, maybe fight some insane survivers or negociate with an agresive army. Any one got ant ideas for how to make this work?