[M is the one who dealt the shattering blow to Estinien during Inoseri. Ciel didn't participate much during Binghe's communion summary, but she did pay attention. Having heard summaries of what happened in Venera from both Silco and Eustace, she's also at least informed of key events. Thus knowing all that...]

We have the pieces in place to lure Estinien, the entity's vessel, to Acamoth, where the Regent will be able to directly action upon them. Given your history with him and your shared Legacy, would you be interested in [...] sending him the invitation?

[M had witnessed firsthand what Estinien and the Innocence are capable of together, what sort of "invitation" this is leaves no room for interpretation. Drawing them to Achamoth is no light matter, but it was initially suggested by the Regent, their mention isn't evoked in vain. The details can come after, once he gives his answer to this surface proposal.]