Other than the river of time explanation, this episode was all over the place, and having had very little to do with the topic at hand. They introduced Scott Kelly by saying he's actually someone who's traveled through time without explaining how and when (I actually had to Google it, because while I recognize the name, I can't quite recall what his amazing achievement was). They brought in a "mathematical oncologist" to talk about brain tumors because...I don't even know why. I would have assumed something about how certain parts of our brains processes and analyzes our perception of time, and how a brain tumor might affect these, but big nope there!
I can only assume a lot of content was cut to fit the time (insert laugh track here) of the episode, but what they churned out was a supremely fractured and incoherent mess of an episode on a topic that deserves far more recognition based in actual science, not pseudoscience/sci-fi.