Reira is right, arguably. But if CY-Ren wanted to murder a bunch of people... well, that doesn't require a setup like this. And it wouldn't achieve anything for her true cause--the Pillar doesn't care if a few hundred or thousand people die. So the only people whose deaths wouled matter are the Guardians. And the Guardians... they don't need him to stay alive, they need to move unimpeded.

"For now," Foster replies. He would actually go with her, as insurance, but if her purpose is stealth, he'd only impede her. But, since she's going, a note.

"CY-Ren already knows we're here." He has no proof of this, but he states it as a fact. There's really no way she wouldn't.