The infantry would be working on their own gear, in the Armory and the PA Bay, going through post combat maintenance and soothing the machine spirits of the Power Armors.
When they are still on duty and not in the Armory/PA Bay, they would be in full combat gear minus the PAs patrolling the ship. In pairs in the minimums. When Off duty they would be using their free time as they saw fit.
As for Other departments the formula you see above would be adapted to your specialty: Take care of your equipment, be working on your duty, and if there is still time in your duty day, you'd be turning a wrench.