This isn't entirely true. Texas schools won't "hold" your app and wait for scores/grades. You don't get special treatment for being in this program, though the students in Med Sci are well recognized. Applying while you're in this program won't put you steps above all the other applicants, but in a sense it does give you a slight advantage in that Texas schools know that you're dedicated to becoming a doctor. When you apply in TMDSAS there's a checkbox you select that shows that you're in the Med Sci program. When admissions committees review your application they can see that. I'll tell you now that there are several people in the program with pretty average to decent stats who still have not gotten interviews yet, or who have only received one/two. It really depends on your particular application. The stronger your application coming into the program, the better your chances are of matriculating to a Texas school directly graduating from here. The weaker your application coming into the program, the less likely you'll be going directly into medical school. With a 34 MCAT though, having two A's in this program might be a good start, but it's not a guarantee that you'll hear anything back at all. Especially when you haven't heard anything back about an interview this cycle. From what I've noticed, the people getting interviews now are the ones that received interviews already in the past but were waitlisted for whatever reason. Not trying to get your hopes down, but you need to approach this realistically.
@HotCheetoChic is correct in her assertion that being in this program can only benefit your application (granted you do well). If you didn't hear anything back about getting an interview this round then you should apply to this program with the expectation that you won't hear anything back during the cycle that you enter. Not saying you won't hear anything back at all, but there's a very real chance that you won't. Apply really early this coming cycle, update TMDSAS with your new grades asap and maybe your luck will change. Who knows?
That said, many students in the program have received and are still attending interviews in Texas. A couple of students have interviewed at out of state MDs too, so don't forget that that's an option as well, unless you're not looking to leave here. And for anyone wondering, several DO schools out of state know about the success of the Med Sci program at UNTHSC as well. If you're really wanting to start med school and don't care about the whole MD/DO and in-state/out-of-state thing, then applying through AACOMAS might be a good option for you.