In any situation in which personal harm seems imminent, make a HT roll. Do not roll until the instant you need to fight, run, pull the trigger, or whatever. Any roll over 13 is a failure, even if you have HT 14+. On a success, you can act normally. On a failure, you are mentally stunned.
Any group of over a dozen people sets off this fear unless they are all well known to you. The self-control roll is at -1 for over 25 people, -2 for a crowd of 100 or more, -3 for 1,000, -4 for 10,000, and so on.
