The 22 remaining recruits, including a mole who is an undercover DS, are sent deeper into the epic and unforgiving terrain of the Isle of Raasay in the Scottish Highlands, to see if they have the mental and physical robustness required to pass this unique version of SAS selection. This stage of the course sees the exodus of four of the recruits as the ex-special forces' instructors push them to control their aggression. For the first time ever, the recruits are trained in firing a gun and when to use this against a potential threat, and pitted against each other in hand-to-hand combat.
