Tamblin hadn't meant to blurt out to Susan that he had been thinking about his relationship with Cascata and how it might change. The matter had been on his mind quite a lot it seemed lately. He had actually meant to talk to Hannah about it. She was less likely to be pushy about the outcome she thought best. On the other hand Susan clearly had some experience now with these matters. Tamblin really wasn't sure about whether Hannah did. It seemed like there was a point where she was interested in Justin Finch-Fletchley, but since neither Cascata nor Susan had made an effort to fix them up together in some time he assumed that was passed.
Of course he could still discuss the matter with Hannah. Just because Susan knew didn't preclude him discussing it with her. And if Susan could talk to Hannah about it she might be less pushy toward Tamblin.
The awkward part would be getting Hannah alone.