Ana
.
Hmmm... You must be riding really fast huh?
Well you'll never catch me 140ft under the ocean's surface too. But I still dive...
Same kind of thing I guess.
You can do anything without going too extreme and still take enough precautions to minimize the risk.
Instead of risk look at the practicality...
I am one of those guys enjoying the both activity.
Which one I enjoy more? Motorcycle of course and it is not because the risk factor.
Will I be enjoying scuba more than motorcycle if it becomes available to me as soon as I step into my garage like when I go for biking... You betcha...
Get all your gear together, put in a car, drive to a harbor, park your vehicle, drag your gearbag to a boat or ferry, buy tickets/pay fees, rent a tank/ pay airfill, go to diving destination and then dive for 30 minutes or so maybe twice or so. Then repeat the most of the process and return home.
OR;
Walk into your garage, start your motorcycle, open the garage door and roll outside to enjoy the freedom of riding.
Location, location, location.
Have your garage attached to a house with water access. Then you just take turns: even days diving, the odd days riding.
No charters, no driving, no hauling gear in the trunk of a car, none of that.