Kini-Nui: Welcome to the hurt.
Though, have to say, I am not entirely sold on Joske running out of EE that fast.
You do remember that just a mere twenty-four hours before he DID go all out on both Agni and Angelus? As in he went dry? And in in that twenty-four hour span he not only went deep-sea diving but ran half around the island before finally meeting up with Heunai?
And for three days before that he was in Ko-Wahi? Granted, nothing terribly major happened there, almost a recoop time, but a recoop in the region that is the polar opposite of his element? Not to mention spending a day running around in a snowstorm meeting his arc-foe and trying to save a damsel?
Before he went there? Ah yes, day and a half before THAT he was climbing the highest tree in Le-Wahi, taking leaps of faiths, crashing through boughs and rooftops, only to be at the mercy of further prank/catapult/flying machines and otherwise getting beat up by hard landings.
Let's not forget the previous day was spent in Ta-Wahi, running around Ta-Koro, dodging Guard members, getting slow-cooked in the under-vents of the city, breaking into vaults and the like.
I mean that should be it-oh wait, almost forgot. The previous two days were spent in Ko-Wahi, braving fierce blizzards, avalanches, wild Mauka, jumping off cliffs into storage sheds, fighting off squads of Makuta's best, all while trying to make it home still breathing, practically dead... only to be partially healed on his return.
...
Yet somehow he did a number on Heuani. I for one - considering how much he has done in such little time - believe he has fantastic stamina... but there is only so much one person can take. I mean all these things have been compounding since day one, none of them fully cleared or healed up from the previous day... not to mention I try to keep to realism. Put all that together yes he would of run out considering just how much he was outputting there. Honestly Toa should run out of EE more often than people say they do 
I hope that shed some light on the situation 