Puzzle solved PP. Your left tube can pick up the egg from the right side or vise versa. As your tube isn't connect to your ovary it is possible for one tube to collect the egg from either side. The tube itself moves slightly and the fimbria (hairy things on the end of the tube closest to the ovary) create a vacuum which basically suck the egg in the direction of the tube. So despite it coming from one side the other side can get it anyway. Also it is very possible that the embie can make it to the uterus but decide to implant in the tube anyway. This is why having no tubes or having IVF does not prevent ectopic pregnancies. Actually with IVF the chances of ectopic are higher still.