Ben Leonard, 16, was on the expedition in North Wales in August 2018 when the horror unfolded.
The group had set off from Stockport to complete a hike up Snowdon but their plans were abandoned due to bad weather.
They instead planned to walk the Great Orme but Ben and two pals became separated from the rest of their group.
An inquest into the boy’s death has heard the trio were unsupervised at the time by any Reddish Scout leaders.
Pal Christopher Gilbert told the hearing how Ben wanted to “look at the coastline” for a while before they decided to wander to find a cafe.
As they started walking back, Ben told Christopher and Alex Jamieson he had seen an “easier way” down that would ave them time.
The friend said he warned the teen away from the cliff edge but there was “no way” to change his mind.
Christopher said: “He went down there and I told him he was being really silly.
“We continued to walk along the footpath and and said we would meet him at the bottom.”
The pal said he later noticed Ben attempting to traverse a wet cliff edge “about 30 to 40 metres away” and commented to Alex it looked “really hairy”.
Just moments later, he saw Ben “slip” and fall from the narrow, 50cm cliff edge.
Tragically, there was no suitably qualified first aider on the expedition and Ben later died from massive head injuries.
The Scout Association previously publicly apologised for the first time and accepted responsibility for Ben’s death.
But the teen’s mum Jackie Leonard said: “It’s five-and-a-half years too late. That’s all we wanted from the beginning.”
The inquest continues.