Some background info on Walz's military rank

[Metaphorical]

30. My brother is a master sergeant

Yes, a second lieutenant is "senior" to an MS or even a CSM, and can order them to do anything ... and, as long as it is a legitimate command, the MS will do it. However, and this is very important, that 2nd Lieutenant will shortly thereafter be called in by the senior commander of the installation (at a minimum a Colonel) and after a long, blistering, and very much one-sided conversation, will be told that if he ever does something like that again, the Lieutenant will be commanding a station in Antarctica.

A command master sergeant has a LOT of clout.