Robin
Robin is an Employee, assigned to do maintenance in tunnels and in Various Power/Water plants.
He is known to not do a very Good Job, hiding Valves, breaking Stuff and generally not being Helpful.
Robin is often the responsible for Injuries too, and even nearly kills Mark at the end of Part 2.
Nobody knows what's actually up with him, if he has a Disease, got poisoned by the infamous Green Shrooms, or is just always Drunk.