Metro Etiquette continued

After the recent horrific killing - a knife! an everyday object! - in daylight in a crowded Washington Metro train perhaps the struggling transportation authority in charge should institute public advisories on how to handle such events. Do we collectively, in whatever car we find ourselves, go in a group to dismember (excuse me, disrobe...or overcome....) the assailant? Obviously if anyone on the car that day had a knife of his/her own perhaps it would have been useful to try a fencing match. But something in the way of rules could be posted: Start screaming all at once (as well as text 311 and 911 and anywhere else you can think of),  start running and kicking and acting up - acting just as crazy as the literally crazed attacker seemed to be. Be prepared for the worst.
Perhaps this: bring with you each time you enter the system a small concealed tube of pepper spray and use it judiciously when necessary. But aim carefully.