He said that despite security measures, they trickled into the television studio hours beforehand claiming to be "artists".
They took over the newsroom and asked for a text they had written about human emancipation to be read---which was "unsigned" according to the journalist, which NET refused to do.
The NET journalist (maybe he was a/the director?) claims that they were not schoolchildren and that they had knowledge of how to use the TV cameras in the studio---implying that they managed to intervene in the regular broadcasting and transmit themselves protesting silently in the studio!
(Or is it more likely that there were some employees at the NET studio who were sympathetic to the protest and did this?)
He also said that it was clear that they were not school students and were adults---however, what we saw were teenagers!! just like the ones in the street----and no one had their face covered.