Honestly, we avoided a massive tragedy at that moment. People described that it sounded like a car or airplane was coming at them at full speed, so they instinctively ran away from the roads. People further away didn't see or hear anything, they just saw a crowd running in panic and so they ran as well. I was maybe 50-100m away from where it happened, and all we heard was noise, yells, and then people running, so the people around me also started running, but we all stopped after maybe 5s.
A lot of people think that our overlord wanted to cause a stampede which would lead to thousands of injuries and just chaos in order to discredit the protests. Or maybe they wanted to launch the cannon after the 15 mins of silence were over, which would cause mass confusion since nobody would have any idea what was going on, but triggered it early. In any case, the psychopath used an illegal weapon to attack people literally standing still and being quiet.
A small correction: there is no leader. The students themselves decide everything on plenary sessions and every decision is executed by working groups that are formed afterwards. You always have different people executing the decisions to avoid any one person being seen as a "leader". And we are slowly shifting to citizens themselves forming local groups in their neighbourhoods with the same organisation.
But yes, the students asked that only Serbian flags be shown, because these are protests that have support from a wide range of people, from anarchist vegans to ultra nationalists, so they want to prevent any division. That doesn't stop some right wing dipshits to bring Russian flags, even though Russia explicitly condemned the prorests as a "coloured revolution", but what can you do.
While some EU representatives from the parliament have been supportive, the EU has a negative image because officials still act like everything's in order. Ursula is set to meet with our psychopathic dictator, and Marta Kos wrote how she had a constructive talk concerning Serbia's steps towards EU integration with the guy who tried to cause a bloodbath during the 15 mins of silence a few days ago. A guy who also officially (as a president under the Serbian constitution) has about as much say as I do concerning these things.