I'm rereading, yes, and I never realized that it was hinted that Pavel KNEW that "Siennas" was Sion. When Sien was thinking of what to name the pup, he thought of naming it "Sion." Pavel reacted and asked, "YOUR name?" or along those lines. Or maybe I'm just overthinking it because Sien (sa-yen / si-yen) sound a bit similar with Sion (