I guess the correct answer is drop out.

When you drop out of something, it means you stop doing something before completing it. For example, you could drop out of a meeting, drop out of a race, drop out of school, drop out of college, drop out of a club, etc.

When you run away, it means you leave a place suddenly and secretly, with the intention of never returning. You can run away from home, run away from your country. But running away from a meeting sounds a bit over the top to me.