I'm not understanding the rule about spending a Void point to "voluntarily not defend" and thereby take a Critical Strike to "gain a tactical advantage". (Pg. 268 of the core rule book, under Defending Against Damage). If you don't defend, you don't spend any fatigue to mitigate the damage. Wouldn't you then take all the damage ? How then would you avoid being Incapacitated? There must be some passage somewhere in the rule book that explains this...but I can't find it. For one thing, I thought the only way to AVOID being incapacitated was to spend fatigue to defend against it. So if you simply opt NOT to spend fatigue, how is that helping? And therefore, how is there any "tactical advantage" to that..? I must be missing something painfully obvious. Won't be the first time, or the last.
"Shattering Parry" (pg. 36, core rule book) is apparently quite separate from the above. (This is where you may spend 1 Void point to dramatically intercept an attack with your weapon to increase the chance of survival, which is also referenced on pg. 270, although in that pg. 270 sidebar there is no mention of spending a Void point.)