Should our home movie night restart when two guests arrive late?

We were twenty-eight minutes into the film when my brother and his partner arrived with dessert. He saw the screen and said, 'You started? Just put it back to the beginning.'

I'd invited six people for dinner at seven and a ninety-minute film at eight. At 8:05 he texted that they were leaving home. We waited until 8:20, then started. Two guests needed to leave at ten, which we'd discussed over dinner.

I offered to explain what they'd missed. His partner said she didn't want to spend the whole film confused. My brother said restarting was the polite thing when someone had brought food. I pressed pause and ended up standing by the television while everyone looked at their bowls.

The pudding was thoughtful. The other guests had also brought food and arrived on time. How should a host handle this without making lateness into a punishment or treating the people already watching as an audience that can simply start over?