This is part of the training for chaplains. The chaplain leading the service is given a scenario and is to prepare a service around that particular scenario.
They typically have 20 minutes with the soldiers in which they pack in singing, praying, and preaching the Word. These are men from Kevin's platoon who helped him in singing Holy, Holy, Holy.
Trust in the Lord with all your heart and lean not on your own understanding; in all your ways acknowledge him, and he will make your paths straight. Proverbs 3:5-6
I hear from other men that Kevin did a great job. I don't doubt it! For the first time in our marriage I've found that I can't be with him when he preaches. That is tough and I miss it so much, but it's so exciting to know that God will use him to minister to thousands of soldiers, and for that I am grateful.