Who lives on the floors of the tower, and why they are so unhappy to find a mechanic in their room. The descriptions come straight from Return to Sender.
A Service Roach on its roundsThe Rat Foreman checks the quotaGlow RatLamp Moths
Service Roachfloors 1-2 · Employee of the month. Every month.Lamp Mothsfloors 1-2 · Five to a bulb. Union rules.Inspector Waspfloors 1-2 · Pest Control. Files you under pests. Stings over typos.The Roach MatronRoach Quarter · Mother of hundreds. Counts them all. Counts you too.CocoonRoach Quarter · Three seconds from now: three of them.Gutter Ratfloors 3-4 · Pot lid for a helmet. Your bolts for a pension.Tidy-botfloors 3-5 · Removes litter. You count.Toaster Turretfloors 3-4 · Breakfast is served. Lobbed.Tinheadfloors 4-5 · Bucket for a helmet. Spanner for an argument.The Rat ForemanThe Sump · Quota: one mechanic per shift.Glow RatThe Glow · A night-light with a tail. Do not pet.Bag MimicThe Glow · Just a bag. With teeth.Concierge DroneThe Glow · Shows you out politely. By laser. Warns once.Big RoachThe Glow · Raised on fallout. Spanners tickle.Pigeonin the fall · Nods at everything. Agrees with everyone but you.Goggle Pigeonin the fall · Your goggles suit him. Everything does.Mothin the fall · Drawn to the light. You'll do.Kettle Dronein the fall · Whistling means boiling. Step aside.
Almost all of them can be given the wrench or landed on. Do not try either with the Bouncer.
This wiki describes the world of the VENTFALL series. Return to Sender is a quick demo and does some things its own way; where it differs, the article says "in Return to Sender".