Ha! Hilarious. And great videography to boot.
Actually we are taught something quite like UW self-defense in most Rescue courses, ie how to approach a panicked diver on the surface.
Re: the subject of the OP...
Read
Solo Diving: The Art of Underwater Self-Sufficiency by Robert von Maier.
Also, recommend taking the SDI course
SDI Solo Diver:
One of SDI's most popular courses, the Solo Diver course teaches experienced recreational divers how to safely dive independently of a dive buddy. The course stresses proper dive planning and accident prevention and in the benefits, hazards, and proper procedures for diving solo.
The SDI Solo Diver programme is well suited to underwater photographers and videographers as a well as any Divemaster, Assistant Instructor or Instructor.
What do I need to start?
Have a minimum of 100 logged dives
Be certified as an SDI Advanced Diver or equivalent
Be a minimum of 21 years of age
I think it is unfair to say that solo diving, under any circumstance, entails a higher level of risk. The properly trained solo diver will of course have trained extensively in self rescue, will have fully redundant critical gear (doubles, spare mask, cutting tools, lights, buoyancy devices, signaling devices, etc.), be equipped with gear that is highly failure resistant to begin with (e.g. spring steel fin straps, continuous webbing harness, streamlined for minimal entanglement hazards, optimal hose routing, no metal to metal connections, no plastic buckles or suicide clips), and will have developed a high degree of situational awareness. Contingency dive plans will have been well thought out. Compare that to a new diver who is paired up with a "same day, same ocean" so-called buddy. Who is at greater risk?
That said, I would not recommend solo diving unless one has been properly trained AND this option lent itself to better accomplishing the dive objective. Best bet... a dive team composed of two or more divers who are all trained to be fully self reliant if required, and are further trained in TEAM diving so that each member considers themselves to be part of a well oiled machine pursuing a common goal with shared resources. That means every diver being fully familiar not only with his own gear, but that of every other team member. Can I find my buddy's spare regulator in a complete silt-out? Can I ditch his weights after he has knocked my mask off during a rescue? Do we share the same set of hand signals? The same SOP for descents, ascents, and emergencies?
Personally, the mindset of team diving as taught by GUE, UTD and others holds greater appeal for me. Most of the techniques and procedures are distilled from decades of cave exploration and other types of extreme environments.
But for those who want or need to dive solo... it's a free ocean. Just get the training to minimize your risk.
Stay wet... avra