Logic behind the scalpel blade is that it can be lashed to a small branch to make a serviceable light duty knife. Unlike a single edged razor blade. It also has a point on it. Makes it very handy for getting a foreign object out of yourself.

Speaking as someone who has been there and done that, it is often easier to remove something like a splinter by cutting the skin over it. This has a couple of advantages i.e.: You don't do more damage trying to drag it back out the way it came and the wound can be more easily cleaned. Preventing septicemia or tetanus is something of a priority in a survival situation.