I'd think about what each does for me AFTER you leave the military unless you're planning to be a lifer....
Good network engineering skills should continue to be in high demand. It's hard to ship those jobs off to India. But the very nature of IT means you should plan on changing jobs many times throughtout your career. The occasional layoff is a hazzard of the profession.
The bio jobs tie nicely into medical and healthcare. As the baby boomers age, those jobs will provide the most job security you can possibly get.
But I'd try to research it a bit more. Find out exactly how transferrable the military training and experience is into an actual healthcare job. If even with all that training, you still have to take 1-2 years worth of classes to get the necessary certifications to work the same jobs in the private sector, then what's the point?