This can't be said enough...
This is a perfect example of how real life is different from the internet.
"Owning a gun doesn't make you armed any more than owning a guitar makes you a musician." -Col Jeff Cooper
Here we have a law abiding gun owner who was attacked by a criminal. As I see it, Daniels would have been well within his rights to put a controlled pair into Foster. It didn't happen though, did it? Why not?
The reason is simple, Daniels wasn't prepared to handle a situation like this. He wasn't aware. He wasn't ready to get his gun out under stress. Even when under full assault, he made no effort to defend himself.
Obviously this is a major fail on Foster's part, but it should be a wake up call for the rest of us. Had this been a true attack by a criminal intent on harming Daniels, his gun would not have helped him at all. In fact, after the criminal dispatched Daniels, he would have had a gun.
No one can be aware of everything all the time. We'll all get caught depending on the situation. Still, there are things we can do to prepare for this. Some empty hand training is valuable like the Focus Training seminar. On going training and practice is better. Remember, just having the gun is not enough. You must be able to bring it to bear.