>>A small number of people were responsible for the riot. They were dressed in black with black masks.
I get an impression of bovver boys possibly with nothing to do with the university, who saw the protest as an opportunity to cause mayhem. Some drunken or over-excited louts then celebrated the escalation, which many an excited youth would have done in our day when everybody didn't have a camera in their pocket and there was no internet for a video of privileged students squealing with delight go viral. Meanwhile the person who pepper-sprayed the young female ticket-holder was not wearing a mask and seems to have been extensively photographed by other disgusted protestors.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1