Quite a long feature just on the BBC news explaining fully the full-risk about the launch and the first 3,000 ft explaining if anything goes wrong before reaching that height - he will die, purely because none of the safety chutes would have time to open. And the Balloon is most vulnerable at the lower heights, being designed for the high atmosphere conditions at 120,000 ft.
and given the balloon alone has a height equivalant to a 55 storey building. The Launch crew are not worried about the Jump itself but are shitting - themselves in regard to this critical first 3,000 ft