I imagine those leaders shouting "Last one to Earth is a rotten egg!" and then looking over their shoulders at the one hitting the ground and thinking Oh, if it weren't for this damn interference, all the glory would be mine! as they're zapped into the return stroke.
oh and Hugh, a little more research discovers that that was a 50kV switch in operation. Apparently that's called a 'jacob's ladder' and it's (I guess) normal. Note the engineer casually walking away in the lower left as they pan out.
LFR! I saw something like that (substation arcing) during a hurricane in Disney once! It was miles away but the noise was INCREDIBLE and you could hear it over the 100mph winds. Amazing, realy. Lit up the sky.
CitrusFreak!! An engineer friend I sent this link via IM confirmed that this is a normal arc during switching. The switchgear are apparently designed to "take it" so he says. And there's no way to completely drain the load (yanno, people want their lights to stay on and stuff). Wicked!
and yes, it's loud as hell, he confirmed that as well.