Lori's death was a true surprise not only because she went into labor after a walker attack, but Carl then was forced to kill her. The fact that it took place so early in The Walking Dead Season 3 made it even more surprising and revealed that truly no one was safe on the show.
You walk outside, you risk your life. You take a drink of water, you risk your life. Nowadays you breath and you risk your life. You don’t have a choice. The only thing you can choose is what you’re risking it for.