The voice-over _clearly_ says: "when two particles are entangled _they can influence each other_ no matter the distance", which is super wrong. If you have two spin entangled particles and you change the spin of one, the spin of the other does not change, there is no influence, only correlation.
Maybe they intended something about the wave function collapse, but they didn't say it. If even explanations coming from CERN get this wrong, I despair for the status of science communication in general...
It really irks me we don't use a simple analogy for entanglement: put two balls of different colors in two boxes. Randomize the boxes. Take one of the boxes to the other side of the room then open it.
You now know the colour of the ball in the other box.
Only you can't implement faster-than-light communication with that so we instead mislead people..
Good pedagogy (like, you know, science itself) starts simple and adds complexity as you dive deeper into the subject.
It's still allowed so long as a) the theory is nonlocal b) the outcome was not actually independent of the observer or c) superdeterminism.
See Bell’s Theorem, this has been mathematically and experimentally proved: https://en.m.wikipedia.org/wiki/Bell's_theorem
This thing that might be confusing you is the action you are taking is collapsing the wave function of a pair of entangled particles (by measuring one of them), so they go from a superposition of up|down to each having one definite value. You can’t repeatedly twiddle the bit here.
Quantum mechanics is so counterintuitive that you have to re-calibrate people's intuition before you can really pick at the confusing parts.
So picking the nit re: wave function collapse is the right thing to do, but it needs to be done in the context of "...but its weirder than just we don't know what the colors are until we open the box. It turns out that...", rather than just immediately "correcting" the partially, arguably incorrect information.
As a challenge to the folks correcting the OP over neglecting wave function collapse, can any of you describe what is wrong with the infinite square well very-first-mathematical-example-of-quantum-mechanics? Aside from the "infinite" part, I mean.
Sounds like you subscribe to the Copenhagen interpretation, whereas they’re using a Bohm interpretation.
They could call it the CERNival.