Wow.
Just amazing.
Those guys were standing a lot closer to some mighty large drops than I'd feel happy doing. Heights don't bother me, but a lot of the ground they were standing on looked loose and crumbly. It might be a highly memorable way to die, but I don't think it'd be a pleasant few seconds while you cooked.
Incidentally, some links showed other footage of a bloke wearing a fire fighter's silver suit and breathing equipment, standing less than 50 metres from the lava lake. I've long wanted to see lava for real, but maybe not quite that close...