OK,that clears that up.However,on your comment that officers can't just quit,it's my understanding that everyone has a term of "enlistment".Mine was six years which,IIRC,was pretty much standard for new enlistees back in '69.Of course when my six was up I said "adios".But I would think that officers have a term of "enlistment" as well...maybe six years,maybe less,maybe more.
Otherwise they'd be slaves.
Upon being commissioned Officers incur and 8 year commitment. Upon completion they are discharged to the In-Active Reserve where they can be recalled should the need arise.
The only way to get out of the Reserves is to resign your commission.
Again it has been a few years but I have personal experience with the process.