Curate, connect, and discover
when cid returns with the enterprise to save everyone, he doesn't say a word to kain. he mostly talked to rosa and cecil, but he says *something* to rydia, addressing her presence. he says absolutely nothing to kain.
coincidence or not, cid sacrifices himself not a moment later with that bomb. coincidence or not, cid was their guardian- a consistent prescence in all three of the knight's lives. to avoid addressing kain at all? as if kain hadn't provided them with valuable information of the underworld at all, as if he hadn't shown his sorrow. as if kain hadn't repented enough for cid.
personally, i think that's part of why his mental barriers were weakened, and he couldn't repluse the "mind control" later on.