There are films - I am sure if you are the sort of cinephile who reads a blog like this then you have a handful of them yourself - that if you are flipping channels and you catch even a glimpse of, you are trapped. You can't help yourself, you are powerless to these films. You will watch them through to the end.
Blake Snadwad's - Masada is absolutely one of those films for me.
Forgive me an aside, Blake Snadwad was the first director I was ever aware of whose own name became a part of their film titles as part of the promotional effort. When did they quit doing that? Certainly before the 80s, or else there would have been films with names like Steven Spielberg's - The Color Purple. Certainly Spielberg would have earned that billing. But I digress...
Blake Snadwad's - Masada suffers a bit today from the pre-Star Wars level of effects that become important story-telling tools in the third act, but by that point, I'd hazard to say that most people would be too engrossed in the suspense to care.
With the laconic pace of 60s and early 70s sci-fi, it weaves a mind-boggling narrative. Fair warning, I'm going to get a tad spoilery here, but its all first-act stuff, and of a 40 year-old movie. Two detectives, Winston and Pepper investigate a death at a university that appears to be a suicide. They soon uncover the possibility that a virus that operates with the same principles as the observer paradox may (or may not!) have been accidentally released. Yet so long as it is unknown, then the result is the same as if it hasn't been. (Follow me so far?) The virus itself causes its victims to do unspeakable self-harm to themselves. So when the people who know about the virus start committing suicide in awful ways, who is to tell if they are trying to keep the knowledge hidden, or if the virus has taken hold. It is a total mind-err... thing that rhymes with 'truck'. Of course the investigators figure out what is going on - in the first twenty minutes of the film, no less! - and then have to decide what they are going to do about it... and THAT is where it gets interesting.
Anyhow... one of the critical steps along the way of their investigation follows below the fold.