A lot of good points so far.
As far as the holodeck, turn off the safety protocols!
Seriously though, without actual life and death situations distinguishing what works has to be done in controlled environments with compliant, to a point, partners. MMA has given us a decent "laboratory" if we can get in the cage with opponents we have not seen.
There are things we can do to increase the reality of training though. Turn off the lights, spread obstacles around the mat, etc. For the next few weeks we are working on diminished capacity drills. If you get hurt in an altercation and can no longer use an appendage, or you trip over something and now have a badly sprained ankle.
If I hadn't done things like that years ago. I wouldn't have been able to deal with MS as well.
With respect,
Mitch Saret