Hitler left the stadium before the medals were awarded. The 100 meter race was the first of Owens' four medals. It shocked Hitler: his Aryan supremacy myth was in tatters. The only thing worse that could have happened was a Jew winning that first race. He likely didn't want to shake Owens' hand.
Actually Owens was not scheduled to race in the 400 meter relay. It came about only because the American Olympic Committee didn't want to cause an international uproar by allowing 2 Jews to run in the 400. So they replaced both with Owens and Metcalf (who took home a slug of metals himself).
I'm not sure if it is still on Netflix, but a docudrama of the event was made called RACE.
