Am I understanding that your goal that customer completes activity X, and email related to X immediately triggers? If so, that's a trigger campaign, you just need a way to know when that activity happens. I'm assuming your fields = TRUE mean they have done a certain action, if that's the case, you need to monitor "Change data value," to when the new value = TRUE, at that point, you can send your email. I'm not 100% sure I follow the exact use case.
It sounds like you might need some "Remove from Flow" steps to go along with triggering new campaigns. Once someone is in a campaign flow, they'll continue until you remove them. Even if they no longer qualify for the smart list that fed them into the campaign in the first place.