have a look at that link and plot out what you think the Command Structure would look like. A visual aid will help.
The “Officer of the Watch” is whoever has the bridge, so if you leave the bridge you would say the Gebbens, “Your have the brigde” he is now in command and has the authorization of a commander.
So who ever is in command in ops, regardless of rank will have have authorisation to launch the QRF.