As the final challenge begins, only five contenders remain. For their final challenge, they must go on the run from a trained team of hunters, with just a compass and a map to find their way to the extraction point. If captured, the recruits will face psychologically demanding interrogation, where they are hooded and exposed to white noise, and face brutal tactical questioning.

The recruits are split into two teams and challenged to transport boats across boggy terrain, as well as performing an open water rescue exercise involving a capsized vessel. Alexandra Burke struggles with a race up a cliff, and Wes Nelson undergoes interrogation by the directing staff, while messages from home put the whole team on an emotional knife edge.

The recruits take on the `redman" challenge, featuring hand-to-hand combat against their trainers, the DS (Directing Staff). Kieron Dyer catches the eye with his strength, but the DS want to know where he's at mentally. Next, the recruits are required to run down a 50m-high pillar face first. Alexandra Burke is still standing but struggling with her confidence. Later, it's the open-water task, where the recruits must dive nine feet deep in low visibility and open a crate of essential supplies.

The remaining celebrities are put into pairs for 48 hours of trust exercises, beginning by rappelling down a 100-foot rock face, relying on their partner to break their fall. Once the task is complete, they must run three kilometres back to the van, but Ore Oduba struggles, leaving him and his partner Shanaze Reade stranded on the mountain overnight. In the final task, the recruits carry a 40kg fuel drum in pairs across four kilometres of gruelling terrain.

Several of the 12 recruits question their place on the course as the gruelling tasks continue - including being pitted against each other in hand-to-hand combat. Saira Khan soldiers on despite an injury, and the recruits' decision-making skills are tested when they're forced to make a call on who to shoot and who to save in a hostage rescue task. Jake Quickenden is brought in for examination as his suitability is called into question.

Ulrika Jonsson and Kerry Katona are among the latest celebrity recruits facing the gruelling tasks and interrogations that make up SAS training. In the first episode, they must brave an aerial assault course designed to test how candidates manage fear, and carry out a hostage rescue in a building that has been exposed to CS gas.