May be late but I still testing how it works, there are some points that seens to be how the trait works:

- reduces your base damage to 40-60%.
- for each zombie in your panic radius add like 5-10% of your damage as a bonus.
- it cannot crit by itself but multiplies a crit hit, both in damage and chance.
- others traits may affect it like Mundane(this mod)
- it is affected by moddles that affects your damage like pain, panic, fatigue or illness.
- it is affected by your skills

I didn't test yet if it works with ranged weapons or car's kill or others mods weapons/damage types but melee works fine.

So this is a very questionable skill. A character who has good skills and does not panic will kill everyone with one blow, and for large groups of zombies (if we rely on your calculations about 10 zombies) there is a fire or a car, depending on the game mode. If you try to destroy such large groups in hand-to-hand combat, a character with little skills will quickly get tired, and if you fight 2-3 zombies at the same time, this skill will only get in the way.