Dog Day Evening - so this is an interesting HK movie now in local cinemas.
It was basically a heightened comedy-drama of a standoff in 2014, where a frustrated i-Cable customer stormed into their headquarters with a knife, over their notoriously difficult and bureaucratic process of terminating contract.
Here, the TV company is fictionalized as Happy TV, which also has a system that pushes the main protagonist to snap and holds others hostage. Like the real Cable TV, they also run a news channel, with graphics vaguely similar to the current Hoy Ch.78:
(Funnily enough, the portayed Cable TV/HoyTV, now in a different pair of hands since 2014, also made a parody video on their social media account based on the movie.)
This film review has more on the plot: