What an average of 99.94 means is every time he went to play he scored an average ~100 runs. Which is just too remarkable. And that too in test cricket.

Test cricket is just what it is, its a test of patience and concentration. You are supposed to play unreasonably long amounts of time(the whole day) in scorching heat. There fore to go in and play that, it just means one thing. Not only where his batting skills top notch in the history of the game, his ability to focus, concentrate has not been matched ever since. Please note bowlers are always on the look out to get your out. And there are literally many way in which you can get out.

This isn't just sport. This is meditation.

Not quite, but close.

In cricket you (and a second batter who is with you) stay at bat until you are dismissed. There are a number of ways to be dismissed, such as being caught on the full or run out, but you don't need to put every ball into play. In order to score runs you generally must play the ball, but trying to score runs increases your risk of being dismissed.

The best batsman are able to both score runs and minimise their risk of being dismissed, and so are able to stay in bat for longer and score higher totals.

Bradman was, on average, able to score almost 100 runs every time he went out to bat, and that is just ridiculous.

well, "putting the ball in play" is not as hard in cricket as in baseball; the 99 refers to runs, not a percentage. but getting more than 100 runs in a game (known as a century) is a reasonably significant feat in cricket; that bradman's average was almost 100 runs is spectacular.