20 Things You Didn't Know About Heat
13. Mann Put His Cast Through Extensive Weapons & Character Training
Mann is well known for putting his cast through rigorous "boot camps" before shooting starts, to ensure they're capable of operating weapons convincingly and also help them become more believably immersed in their characters.
For Heat, the cast was given weapons and tactics training by ex-SAS soldiers Andy McNab and Mick Gould, and Mann also arranged for the cast to go on various excursions to meet like-minded individuals.
For example, Val Kilmer, Tom Sizemore, and Robert De Niro were taken to Folsom State Prison to talk to actual professional criminals, while actor Mykelti Williamson confirmed that Mann had the actors playing cops go for dinner with real LAPD detectives and their wives one night, and the actors playing criminals go for dinner with professional criminals and their wives another night.
Above all else, Mann wanted his cast to understand how their respective groups socialised and conducted themselves in public.