Confusing scenario

Ambulance parked

Here’s the setup for a short story, or a scene in a longer piece. The place: an urban wasteland, relatively speaking, near an old railroad line converted into a walking path (aka the BeltLine) and near a transmission station, next to a drainage ditch, under power lines, and near a mixed-use complex that’s mostly housing (converted from light industrial) on the other side of the ditch. The confusing element: an ambulance, parked, lights flashing, no one around (I watched for several minutes, and just saw the running lights). Additional aesthetics: a grey, overcast sky beginning to clear, a quiet weekend morning with little human activity out-of-doors due in part to a stiff breeze and relative cold.

Possible story lines (a start): Is it a simple driver-hiding-out-from-work? Is it more nefarious?