Need help with mission 4 (the first hummer mission)

[Guest]

I think this is mission 4. It's the one where you have to drive the hummer through town and open up a couple of gates that are across the road. Near gate 2 a raider offers to give the location of the key if I provide him with some food. Long story short, I started walking away to look for food and he started shooting me in the back. Now he's dead, I still have no food (like it matters) and the key is nowhere to be found. At least nowhere that I've looked. Can anyone tell me how to open the second gate. I've tried blowing the door to the control shed, lockpicking it, trapping it, running into it with the hummer, etc. Can't find the key. Can't get it open. Any help is greatly appreciated. I feel like a heel being stuck there.

 

[Guest]

You kill that guy either way.

The key is on the leftmost building on the left side of that street you are just walking down, there's a chest on 2nd floor. There are 2 ladders to reach the roof, both were pretty easy to find for me, just scout around the southeast and southwest sides of the building.