The tanks shown were leaving the square, which was evacuated peacefully. Even wikipedia backs this up:

In 2011, three secret cables from the United States embassy in Beijing from the time of the events were leaked and published by WikiLeaks, all of which stated that there was no bloodshed inside Tiananmen Square itself.[185] Instead, they said Chinese soldiers opened fire on protesters in Beijing outside the square, around Muxidi station, as they fought their way from the west towards the centre.[185] A Chilean diplomat who had been positioned next to a Red Cross station inside the square told his US counterparts that he did not observe any mass firing of weapons into the crowds in the square itself, although sporadic gunfire was heard. He said that most of the troops who entered the square were armed only with anti-riot gear.[185][207]

Conflict between rioters and the PLA outside the square around Beijing resulted in ~250 deaths total, soldiers and rioters combined, and the violence was kicked off by rioters lynching and burning alive officers 2 days prior to clearing the square.