Phoebe reads the body language when Kate spins away. Anyone else probably wouldn't know what that meant. It's not that Phoebe is all knowing, not even close to that. Or even that she knows Kate so well that she knows what it means. No, Phoebe recognizes it because she went through it with Cole. It's a sharp pain that even now sometimes catches her unaware. She will always love Cole, that's just something that she lives with, but she knows they aren't good for each other. It doesn't mean that it won't sometimes feel like a phantom appendage that was cut away. It does.

Phoebe might have no idea as to the who, beyond it isn't Declan because Kate already dealt with that, but someone was causing Kate emotional pain. Someone that she couldn't reconnect with for whatever reason. If Phoebe had to guess the reason, she'd say someone departed the island.

"Hey. Talk to me."