The route starts up a crack and is immediately hard (and harder than it looks). The climbing is a little off balance and the gear before the crux move is hard is in an awkward placement, made more awkward by the position of the climber. The leader had climbed up so that their feet were around 3m off the ground. They had a good nut placement by their feet. The leader struggled to place a piece of gear above their head in an awkward slot and became pumped in the process. Once they had placed it they clipped the same rope as through the first piece and then sat on the rope. The small cam they had placed ripped out and the leader was flipped upside down by the rope before the first runner caught them, stopping just before the deck head first.
Be careful that runners you are going to weight are secure. The cam was in a tricky section of crack and was difficult to check.
Near the bottom of a route in particular pulling through slack to clip an above head runner places all of your faith in that runner. Clipping the runner with the other rope would have reduced the slack in the rope which ultimately caught the climber and their fall would have been shorter, with less chance of hitting the deck.
Inspecting the crack more thoroughly from the ground first might have given more information about the runner placements and meant the leader became less tired trying to place them.
Trad rock climbing
Slip, trip or fall, Equipment failure, Belaying failure or error
Rescue Services Involved?