[quote=@Flamelord]
Tatsunoko is holding a Heroic Spirit hostage.

....Tatsunoko does realize that even the weakest Heroic Spirit is like 10x as strong as a baseline human, yes?

EDIT: Also, unless Mizore has a trait or NP that says otherwise, every other Servant in the room knows that she's a Heroic Spirit because they can detect her.
[/quote]

Tatsunoko picked her because he didn't know she was one.

Hmm... you make a fair point her... she still doesn't want to reveal her powers though