what are you majoring in? people say major doesn't matter, but it does, especially at UNMC, because science majors (especially biology) are generally given preference...
also, was all of your volunteering/research experience ONLY at UNMC? if so, you might want to diversify...and also do NON-HEALTH related volunteering.
I'm also a Nebraska resident (30ish MCAT, 3.78GPA at Emory U., chemistry major), I applied in 2010 and didn't get in (they sent me a rejection at the last minute...like March 15), and then I called them in April and they (meaning Gigi Rogers) told me that my main problem was lack of health-related volunteer experience. I had already knew that personally, and by that point I already had nearly one year of health-related experience because I started volunteering (at a hospital) one month before I started my application, and I have continued up until now...I've also been working as an entry-level biotech researcher since then, and I've gotten a couple of acceptances this time from other schools but am still waiting on UNMC...