Film is not developed under a red light in a dark room, as shown. The chemicals are too sensitive to light, and exposing it to even a tiny bit of light will fog the picture. The film is placed in a light sealed canister, either under total darkness or using a special light sealed handling bag, that allows chemicals to be added and removed without exposing the film to light. Film paper onto which a picture has been projected is, however, developed as shown.
The handcuffs that are used are of the type you can loosen yourself when you wear them. There is a small clip on the side, next to where the key goes. The clip is clearly visible multiple times.
At one occurrence the clip even clips one bit, when she's digging in the floor boards.