Togami wouldn't allow that option. If he can't bring his servant in, nor can the others such an exception would be biased, and baseless. Leon would agree he doesn't like the risk if his Saber, a literal saint incapable of doing anything expressly evil, can't come into a place of her own faith why should other servants. And Father Walter while he'd sympathize with Kiyo wouldn't allow it because he's a firm believer in the fact that rules are meant to be followed. He will not risk Kiyo's presence as it not only offends the other masters, but it would also be a slight on all the other servants who would come only to be stopped at the gate. No one knows about Kiyo's current status, and if they did it'd just make the more antsy to get her away from them.

Short story shorter: The church won't show bias, nor would they risk the other masters safety, and half of the current masters present wouldn't allow it anyway.