I need to speak to whomever is in charge.
That would be me.
Lieutenant Pel Ebbirnoth at your service.
"Lieutenant." An ancient term whose original meaning was "One who stands in place of someone else." The "tenant in lieu of the master."
Which is to say, you're not in charge, b ut you might know who is.
That might be what the word used to mean. Right now, though, "Lieutenant" means I get to decide who Sergeant Schlock shoots first.