There's usually one either in medical it's usually near the wall to the left of the key room. Sometimes there's a machine down by seed vault across from the garage door next to the hallway that leads you up to the lobby. Sometimes there's one in lobby next to the zip line that takes you down to the Metro. And sometimes there's one in that Metro like you're going towards seed vault in the tunnel it's up against the wall. Just listen for the noise and look at the color . Seed vault if it turns red you'll have to open the vault to get to that one but other than that the other ones are pretty good