Editing DOGFACES Rule Alterations (section)

===INSTANT DEATH===
At the GM’s option, a Toughness saving throw against lethal damage that fails by 20 or more can result in immediate death, rather than changing the character’s condition to dying. This is suitable for campaigns with more realistic lethal damage; such massive damage is almost certain to kill poorly protected or unlucky characters. The players can, of course, still spend hero points to improve such poor Toughness saves.