During construction of Canary Wharf they used to jump the crane which was on steels in the core. They had 2 electric cradles but the guys used to get out of the core on the steels leaving the cradles suspended in mid air once the steels were pulled out by an external crane.
We used to erect a cantilever out to one cradle and then have to put a 13' board across to the other cradle and walk across. One of the guys used to say "I dont get paid enough to do that." Colin you know who you are!!!