In Run & Gun, the consequences of being exposed to temperatures below freezing are described as follow:
The risk of frostbite begins when a character is exposed to a Moderate or greater severity environment — temperatures below freezing. Each Environmental Severity increases the damage and decreases the duration between tests according to the Frostbite Damage table.
It is followed by a table indicating the damage and duration between tests, depending on the environment's severity.
But... what test? No matter how hard I look, I can't find any test mentioned anywhere. Does it refer to something in another part of the book, or another book?