I've set up an extra session on Monday to do exactly that. I plan to just say I am trying my best to respect his boundaries (no phone calls, no emails), but that I need him to respect mine. I do not want new topics/connections in the last 10-15 minutes. I want to focus that time on wrapping up, and I expect him to learn some strategies to help in closing down a session. (Right now, when I do what SD recommends and say "why raise this with 10 m left?" he goes silent! Just stops talking!)

I don't know if I even want to ask him "why" - to me it doesn't matter. I know what I need in this situation and it isn't to have topics that are hard enough to contain within 50 minutes brought up when there's less than 15, then kicked out. Even that being hard enough, the fact that he is doing it AFTER I've already asked him not to because it hurts me makes it seem like some kind of betrayal or purposeful sadism.