Have you been to a big city mall lately?
Scuba is seen by some as a lazy mans extreme sport. You can tell your friends you dive, and they think it's dangerous or cool, and you don't have to break a sweat except to cart your tank back to the car.
7:15 miles are not something most people can run without training. I picked a random 5k race with a lot of participants, and a 7:15 pace puts you in the top 10% of finishers (3 miles, not 2).
Cool Running :: 14th Groton Road Race Race Results