Yeah, Ishida destroyed a lot of souls during that contest of theirs. Not to mention his hands were bleeding by the end. He pretty much used up all of his spirit energy I would imagine or at the very least, his endurance. Fingers could not take the energy anymore or something like that.

But I would imagine that the kids with Urahara did the same thing. Soul Reapers are the only one that can do the cleansing, so they killed souls as well. But I guess they realize that and just know there is no other choice in the matter. Though we also do not know how many hollows that they killed. I do not even remember the number that Ishida got up to. I think they were counting into the twenties maybe higher. Though I think that Mendos Grandai probably counts for like a few hundred on Ichigo's tally. Since it is a ton of hollows crushed and folded to make one nasty large hollow.

Though looking at the thing it did not seem that scary. I would imagine that it is probably a nasty thing in a fight. But Ichigo was able to injury it slightly. So I would imagine that Renji or a captain could have done the same. Probably some of the higher seated Soul Reapers as well. But who knows how much spirit energy Ichigo released at that point.

Though his sword was going crazy along with his energy. Ishida had to far off a lot of arrows hands bleeding. Ichigo's power was probably too much to stand for Ishida. I did not completely follow everything that happened there. It was like a huge release of energy and made him unstable or something. So then everything just came rushing out or something like that. The result would have been Ichigo's death if nothing was done. It was a very curious moment, but it was a bonding moment for the two of them as well.