This is an interesting video. The Bad Guy enters the store with a covered face and even though it is winter and the weather is nasty, it is customary for people to uncover their head/face entering a locale. This guy did not: First flag.
The pharmacy technician (white robe with patch on arm) feels something is wrong, you can tell by his body language. He is in a narrow place so he leans his upper body back trying to place distance from what he may not even yet consciously (but surely subconsciously) perceived as danger. The Pharmacist does appear to have noticed the Bad Guy and it seems to be some sort of quick exchange with the Pharmacist pointing his hand at the Bad Guy who finally commits to action by drawing his gun. The Pharmacist reacts by drawing his own gun out of the view of the Bad Guy and engages him.
My only “criticism” is that the Pharmacist shot single shots instead of controlled pairs or more. I have the feeling that the Bad Guy’s gun did not work for whatever reason, but in such a short distance and with innocents around, I would like to have seen more shots directed to the BG in the hope that the shock would stop him from even thinking about responding like we see in the video.
But it worked, the Bad Guy is under hospital care in handcuffs and everybody in the pharmacy is OK. So damned good job.