Interesting video:

I love these kind of videos as they are great learning tools to prepare you in case you are faced with a similar situation. Armed robber goes into a Cell Phone store where two employees are working. He submits them a gun point, gets cash and leaves. There are two camera angles and they yield great info.

First: Beretta 92 or clone. Cocked & finger on trigger.
This is basically disaster waiting to happen. One loud noise, one startled robber and a bullets goes out the barrel.

The employees do the smart thing and just drop the cash on the counter.

Some falls to the ground and the bad guy, very obligingly goes after it.

Twice….

The bad guy loses control of the victims for some 3+ seconds.  That is plenty of time to do something if properly trained.

If you have quick access to an exit, even if it only leads to a back room with a door you can lock behind (red arrow), you may want to take it.

But we also have another person, in this case a pregnant woman with no obvious access to a safe area. We do still have an armed criminal on the store and the possibility that he may not want to leave witnesses behind or just shoot for the hell of it. Again, three seconds is a long time if somewhat properly trained with a firearm and mentally ready to do what needs to be done.
Here is a classic self-defense video. Robbery at a Motel 8 in Columbus OH, 2006.

And here you will find the news item and the comments of the employee. More lessons to be learned there.

Feel free to add your thoughts.