This is a propaganda video where most of the "erie" parys are just video editing and commentary, not demonstrated through evidence or interviews. It is a good example for developing your own media criticism skills. I'll make note of one outright falsehood and invite you to critically analyze the video further.
They lied when they said those attending didn't go home. They literally show them arriving and going home on buses multiple times. Rather than note their own inconsistency in narrative, they try to characterize this as erie and scary as well. Oh people line up to get on buses! Follow that bus! Oh it just goes to a "government facility" and they leave to do whatever they want to afterwards? What government facility? They say they are "processed" first. Where is the evidence of this? All they show is people leaving while the bus they were on is stopped.
The BBC has a history of pushing this kind of bad faith propaganda. They even do things like get down into ditches to make "scary" angles for boring things and desaturate the videos like it's reality TV and you need to emotionally manipulated to know what the bad things are.