Bring water to boil in pot.
While waiting for water to boil: Place plastic wrap over a small bowl, so that you can crack the egg into the plastic wrap. Twist ends shut. It doesn't have to be completely secure, just enough so it doesn't open up.
Place plastic-wrapped egg in water, at a near boil (so that you can see bubbles forming in the bottom of the pot). At first I was worried about the plastic wrap melting on the bottom of the pot, but it didn't. Cook for 5 minutes, to get perfect runny yolks. Remove plastic-wrapped eggs from water, unwrap, and serve. As a bonus, clean up is easy!