Your three sided debate maps on to the Collective Intelligence Project's "Transformative Technology Trilemma", which has corners on "participation", "safety", and "progress". https://cip.org/whitepaper#trilemma

What is the source on this being slowed down by 100x? 

Here it says Magyar filmed at 1300 fps, and the video info says 50 fps; does this imply 1300/50=26x slow down? 

Also, if the video is 120 seconds long, 100x slow down implies the train stopping took 1.2 seconds, which seems too fast. 

26x slow down implies the train took 4.6 seconds to stop, which seems more plausible to me.