What is the big Gas Station and how do I open the garage?
Some gas stations are bigger and have a locked garage with a car inside. On the map they're marked as Gas Station, like the small ones.
How to open the garage:
Find the Gas Station Keys on a table inside the station.
Press the Button to open the first door.
Go to the locked door with a padlock at the far end of the station. In the PADLOCK window, put the keys in the INSERT KEYS slot and confirm. The keys are used up and the door opens.
Switch on the diesel generator. The lamps light up and the garage door rolls up.
Inside is a Car (the model is random) — full health, with an engine and battery already installed and a quarter of a tank of fuel.
The station resets about an hour after the keys are taken, once no player is inside. The doors close, the power goes off, new keys appear and a new car is placed in the garage. Anything left in the garage when it resets is destroyed — take your loot with you.
Also at the station: a Recycler, loot crates and barrels, and an armed guard. You can't build there.