My take on the whole military/naval academy-followed-by-service thing is close to the way the US Armed Forces handle it: If you go through the Academy and graduate, you are commissioned in the Academy's service (Army for USMA West Point, Navy for USNA Annapolis, Air Force for USAFA Colorado Springs) and have an eight-year obligation on active duty (there is a Reserve option, but I couldn't find details - it's longer, though). If you fail to graduate, you incur debt to repay the US for your (partial) education; the rate is comparable to the so-called Ivy League private universities (about US$60,000 per year). If you are found unfit for service for other than medical disability incurred as a result of service (discharged other than honorable circumstances), you incur a similar debt (though it might be pro-rated for the period that you served in good standing). You do NOT have a choice about going into the service if you graduate - you WILL serve your obligation. Thus:
(note: I rule-of-thumb the Imperial Credit at Cr1 to US$3)
Szabo Istvan is accepted to the Imperial Naval Academy at Regina. Midshipman Szabo graduates at a mid-level in his class; not a spectacular student, but apt enough, and he is commissioned an Ensign in the Imperial Navy, in which he is now obligated to serve two terms. At the end of his first term, there are no black marks against him, and he enters his second term, still an Ensign. He applies for promotion, the review board finds no reason to deny, and he is promoted to Leftenant, Junior Grade. At the end of his second term, there are still no black marks against him, but Leftenant (J.G.) Szabo doesn't really feel that the Navy is where he belongs, so he resigns his commission, and seeks other employment. He has the skills he developed in the Academy, plus those developed as part of his active service (consult the Traveller rulebook for details).
Ephraim Eral applies to and is accepted by the Imperial Military Academy at Capital. His marks in earlier schooling were good, but he never developed the self-discipline needed to be truly a good student. This does him a disservice, and after two years, the Academy dismisses him, and he receives notice that he will be required to reimburse the Army for their (failed) investment in his education. As a result, Eral has no useful skills, and debt of Cr40,000.
John Carter is nominated to the Imperial Military Academy, Terra. In spite of the handicap of gravity 2.5 times that of his native Mars, he graduates at the top of his class, and is one of the exceedingly rare graduates that is commissioned directly to First Leftenant (house rule: roll 18 [natural only] on 3D) instead of the normal Second Leftenant. He is sent to the Solomani front, which has heated up (again), and distinguishes himself in battle, earning a battlefield promotion to Captain. He does not face a review board at the end of his term; rather, he is retained for his second term both as part of his obligation for commissioning from the Academy, and as part of a 'stop-loss' order issued out of Army HQ/Domain of Sol. He serves two years more, at which point a cease-fire is negotiated. Shortly afterward, an accusation arises that Captain John Carter committed atrocities during an occupation of a Solomani world. The investigation does not substantiate the accusation, but there is enough question that Captain Carter is brought before a court martial, and, while the Army does not feel they can stockade him, they can and do discharge him from service, other than honorably, for 'conduct unbecoming an officer of the Imperial Army'. As he has not completed his eight-year obligation to the Army, he additionally incurs debt for his education, prorated against his service, so that, having served six years of his required eight, he only has to pay for one year of his Academy education, or Cr20,000. Carter has some skills from the Army and its Academy, but with a discharge under other than honorable circumstances, his possibilities for employment may be limited, and his debt difficult to discharge.
NOTE: There is a service obligation associated with the United States Merchant Marine Academy (USMMA) Kings Point, as well, but it is not as "cut and dried" as the other three service academies. For Traveller purposes, I would treat the Merchant Academy the same as the Military or Naval Academies - two terms of service in the Merchant (Merchant Marine) career, or incur debt.
For ordinary college (i.e., not associated with a particular Imperial service), I would leave it up to the referee's discretion whether the character graduates (or flunks out) with debt, and if so with how much.