What happens at the massive registration in the stadium?

There are perhaps 30,000 people at the stadium. Jews are told to line up and approach the tables to be registered. The elderly, families with many children, and people without work cards are sent to the left, while men of working age are being sent to the right. Vladek, Anja, and Richieu are spared. Vladek's father approaches Mordecai's table and is also sent to the right, but Fela and her four children are sent to the left. Realizing this, Vladek's father sneaks over to the left to be with his daughter, and none of them are heard from again. In all, maybe 10,000 people are sent to their deaths from the stadium.