[@Raineh Daze]Eh, still highly unlikely. While I guess her Mystery might help her resist it - since in an odd sense, her Mystery rank might actually be HIGHER than Assassin's since she's a modern spirit and all - there's just the sheer volume and power of the curse to take into account. She'd have a better chance if she was inside her Bounded Field where her Origin gives her even higher priority, but out here, she'd be just as screwed as anyone else unless she realized somehow that Assassin was making her move and just had Saber nope them both with a Command Seal.

Although, if Assassin approaches to take her hostage or attack her, she might run afoul of the curses that Mira placed there in advance when she mistakenly assumed that Johanna was Assassin's Master, so that might also help her chances.