This is a pivotal moment in Doctor Faustus because it shows that : Faustus learns that death is inevitable
Pivotal moment is an important point that marks the change in direction. It is the center or a story and everything that relates to the topic turns or depends on that specific point.
The hike to Castle Rock is stressful, but once Ralph and Jack scout it and determine there is no Beast, the remaining boys begin to distract and entertain themselves by pushing a large rock off the cliff into the water, foreshadowing the future use of that strategy to "defend" themselves.