I'll also note that you're not going to die if you don't use a torque wrench. I once had a roomate that forgot to tighten the lug nuts on one of his wheels after doing a brake job. The lugs were only hand tight on that wheel
So he goes to work(several miles via the freeway), works his shift, and then on the way home he calls me and says his car is shaking really bad. I meet him in town. He tells me that it started shaking shortly after he left for work the day before. I walk around the car to find two of the lug nuts on that wheel were missing and the other three lug nuts had almost completely backed out! Keep in mind, these were only hand tight. As soon as I showed him, he realized that he had forgot to tighten them with a lug wrench.
The point is, it's highly unlikely that all 5 bolts will back out simultaneously and even if they did, you'd know something was wrong immediately when your car begins shaking violently.