The next senior URL would assume command.That would be quite the experience to have your skipper shot down. Just out of curiosity, if CO and XO are both lost, does the OPSO assume command?
I had "my squadron" as "acting CO" for a little over a week when I was the Admin Officer. CO was on a pre-deployment trip and the XO went on emergency leave.
Every day when the CO called I threatened to use up all the CO awarded NAMs and designate every 3P as an IP.
I did use my temporary "power" to sign all the outstanding squadron instruction revisions the CO had been sitting on. It took him about 3 weeks after he returned to realize they were no longer in his hold box, a fourth week to cool off and a fifth week to thank me. I got a lot of the Admin Departments backlogged work cleared up that week.....