There was still quite a bit of time left after Fang Zhao and company filmed in the kitchen. Kevin Lin saved it for filming folks returning from trips beyond the base.
The soldiers returning in the evening were mostly career soldiers stationed on Baiji, not regular conscripts. Most of the more challenging tasks like hunting, scouting, and so on, were left for career soldiers.
It wasn't just the conscripts who wanted to get on camera, the career soldiers did too. They were often away for years at a time and missed their families.
But only soldiers who weren't assigned to classified missions could be shown on air.