Read it a few days ago, not long after it was posted.
It's pretty good, though I would say a bit too fast paced in some ways. Like Integra's desperation could have been spaced between some moments of her doing paperwork, like one easily ignorable gurgle before she starts, and so on.
On the part with Seras, I would feel some extra insight onto WHY she didn't/couldn't poo would be good. As far as I know, most vampire "biology" never really brings up this fact, for obvious reasons. And I know the manga/ovas, and the anime only briefly made it seem that eating was akin to drinking piss water for the poor girl.
Still, a good effort overall, though I would feel that Integra might have been a little more reserved in sharing a toilet, at least to the point of keeping quiet for both their sake as though sitting adjacent to someone.