A few others before me discussed the clear detachment of both narrators to the traumatic events that they survived. I too was struck by this, and also at how little connection there seemed to be between Simpson and Yates. Throughout the disastrous events of the text, each man seems to be acting independently from the other. From Simpson's original description of Yates, I expected a much closer bond: "He was an easy friend: dependable, sincere, ready to see life as a joke...I was glad that we had chosen to come here as a two-man team. There were few other people I could have coped with for so long. Simon was everything that I was not, everything I would like to have been" (20). The two appear to appear to be close friends. Yet the disconnect between them as partners becomes apparent at the start of chapter 5. As Simpson falls through several crevasses and struggles to free himself, "From a safe distance Simon [watches Yates's] struggles with a grin on his face" (69). Far from rushing to his friend's aid, or at least ensuring from a safe distance that he his uninjured, Yates looks on and laughs. At this point the two are not in much danger, but this moment seems a harbinger for the way the two work together, yet separately, after Simpson is injured.
After his fall, Simpson notes that "an uncrossable gap had come between [them] and [they] were not longer a team working together" (75). Yates lowers Simpson as quickly as possible, seeming to care little for the excruciating pain he is causing Simpson. Simpson for his own part denies the seriousness of his injury because he assumes Yates will otherwise abandon him. The two move forward, doing little to check in with one another. I think Yates only asks Simpson once how he is feeling after the initial accident, and Simpson never asks Yates what he feels is the best course of action. Only when their progress is successful does Simpson consider himself as part of a team. Otherwise he is cursing Yates's name.
Still, I understand why this disconnect was necessary (as much as I can without ever having experienced anything like it). Both men survive the climb, meaning that working with their own self-interest in mind was likely the best course. If Simpson had cared for Yates's life over his own, he may have needlessly been left to die higher up on the mountain. If Yates had felt more of a connection to Simpson, he may not have cut the rope and might have plummeted to his death.