About 50 years ago I went through DRT (Disaster Recovery Training) in the U.S. Navy, and one of the features/lessons was to use rope to tie up a sling seat--which you would then climb into--then, with a 1/4" line attached to the back and let out by another trainee, you leapt off the top of a five-story tower, a heavy carabiner at the top of the sling hooked over a 1" rope, and allowed to fly downward at a 30-degree angle, to where the heavy rope was tied to the bumper of a "water buffalo", a 1,000-gallon water tank atop an 10-wheel military truck.
Not exactly the 1,100+ foot height of the Euromast Abseiling, but I totally understand the rush these folks are feeling. As always, C., another great capture.