Most folks simply haven't put any amount of careful thought into a technique that is safe to use for carrying, drawing, and reholstering.

1. Guy was either pulling his gun out of or putting it back into his holster or pocket without some form of holster.

2. He had it out, dropped it and attempted to catch it.

3. He was pocket carrying and had items aside from his firearm in that same pocket.

4. Or he had the the world's slowest hang fire [Joking]

On a serious note if you have a gun on you in a theater, keep it there unless you absolutely need it out.
If you are carrying without a holster or a trigger guard cover slap yourself. (Got it you pocket carry your MasterBlaster 6000 with a 10 lb + double action trigger.) Which costs more? Killing, or injuring yourself or a couple of good holsters? If you must pocket trigger keep that pocket reserved for JUST THE GUN!

That rule about keeping your finger straight and off the trigger should also state and keep your digits firmly registered away from the trigger and trigger gaurd area. If I had a dollar for everytime someone pulled a handgun out of their holster /pocket/ carry device without a decent grip on the gun I would be in the Bahamas sipping a cold beverage for a very long time.

Lastly make sure your clothes and holster selection are conducive to drawing /reholstering. No drawstrings, excessively baggy clothing, or a holster in some God Awful hard to reach spot like a floppy shoulder holster, small of the bag, or obscene distance cross draw.