Most people teaching how to escape from handcuffs use some improvised tools rather than slipping out.
Guy teachs how to open handcuffs with a hair pin
Some people go for brute force techniques.
Guy breaks handcuff
And some really slip out, but mainly due to poorly placed handcuffs (generally on the lower part of the forearm), or because the person has very peculiar physical features (e.g. thin hands). So, I think that Escape is a bit cinematic as described in Raw. Is there any other rule for it in the books?
Personally, as a house rule, if a guy has Flexibility or Double-Jointed, generally I apply raw rules. If not, I apply Equipment Modifiers to Escaping rolls, and someone trying to escape from handcuffs would have -10 without equipment. With equipment, like an improvised shim, I would drop it to a regular -5, if the hancuffs are double-locked, or to 0 if they are not.