Bishop and Jersted both know that Bishop’s claustrophobia is probably a reaction to the lack of oxygen at this altitude. Humans need oxygen to function. Without enough oxygen the human body and mind cannot work properly, and all kinds of problems can begin pretty quickly. An irrational or exaggerated fear like claustrophobia could certainly be a side effect of not getting enough oxygen. Many climbers report strange behavior and odd thoughts when they are at high altitudes. Most of them feel very uncomfortable and even quite sick.

After several hours of fighting his fear, Bishop makes a difficult decision. He increases the flow of oxygen from his oxygen tank into his sleeping mask. It is a hard choice for him to make, because he only has a small amount of oxygen with him. The two climbers have been using as little oxygen as possible so they will have enough to finish the climb. But, Bishop cannot stand the discomfort any more. The small amount of extra oxygen flowing into his sleep mask makes Bishop feel better. Eventually, both men sleep.