The police interfered in order to make way for people willing to leave the supermarket. In the video, the police is saying "Everybody back off, otherwise you'll hurt each other!"
This is really terrible - I'm totally filled with grieve for people who sacrificed their night sleep to get cheap stuff, without even being guaranteed a chance to get in. Looks like a flashback from the USSR times, when there was a shortage of everything and people had to stand in long lines to get oranges or sausages. People are feeling uncertain and scared - they want to have a stock of goods in case the situation goes even worse.