We referred to it as the half year HPSP. The program works like this: You apply for both the HPSP and GME at the same time. You need to have everything ready for commissioning if you are accepted into the GME program of your choice. So, you have to do the physical, the background check, and have your name submitted on the scroll. The professional recommendation is from the GME selection board. If they want you, you're in. While you are working with the recruiter, you would go through the standard GME application process. Interview and perhaps do an audition rotation with the program of choice. When the GME selection board meets, you are considered with all of the other HPSP/USUHS/HSCP students for the internship of choice. If all were to go well and you were selected for the program you wanted, you would be enrolled in HPSP for the final semester of school. The Navy would pay for that last semester, give you the stipend, and other books etc. You could also elect to take the $20K signing bonus. If you don't get what you want, you walk away and owe nothing. The contract would not be signed until you were happy with what you got.
What you get: 1) The internship of you choice (assuming you are selected). This is only a selection for internship. You would have to apply for GME-2 like everyone else (unless they offer a continuous contract which only applies to FP and Psych at present). This would entail the risk of being a GMO. Now I will say that ENT has been pushing hard for straight through training. The ENT RRC has been griping. That is a trend not a guarantee.
So if you take the deal, know GMO time is a very real possibility.
2) Last semester of tuition paid
3) 5 months of stipend
4) $20K signing bonus
What you owe: Minimum service obligation of 3 years (4 if you take the $20K) of which internship counts. If you go straight on to GME2+, you would owe year for year and the MSO would be moot.