Mike at ENDO posts this video:
Overall good advice. Active shooter situations are bad to be in. If you can avoid contact with the shooter you’re better off for it. Also good on them for pointing out that fighting back is a valid plan. The whole “Playing Dead” generally seems to rely on the “dumb luck” factor as we frequently hear about people getting shot whilst playing dead. Also your adrenaline is going to be RAGING, I don’t know how “dead” I’m going to look with my pulse and breathing severely elevated by fear and self-preservation.
Also while unarmed people attacking is what kept the body-count so low in the Tuscon shooting, why rely on improvised weapons when you can have the real deal. Mike has a screen cap on his blog showing that this was shot in Texas at a “Gun Free Zone” (Bonus points for being realistic, those 30.06 signs are active shooter magnets!). Ideally you’d engage with a gun…but in a gun-free zone that you wish to comply with for your own reasons, look at your local law and company policy. Will a knife or an impact weapon keep you clear of politically correct scrutiny?
When in doubt those Fire Extinguishers DO work well as an impact weapon. I would advise against using it as a blinding spray, tho as you’ll likely get as much of the powder as the attacker, and be blinded by the cloud.
Still beats the crap out of the “Play Dead and Comply” advise of the 80s and 90s!

