Flee Battle

Fleeing is a party action. On any PC’s turn, any player can propose that all the characters flee the fight. If all players agree, they successfully retreat, carrying any fallen heroes away with them. The party suffers a campaign loss. The point of this rule is to encourage daring attacks and to make retreating interesting on the level of story rather than tactics.
Flee is a rule that empowers the party to take greater risks, knowing they have a narrative out if things go South fast. It can also save the party's bacon if they are being defeated by a monster that, on paper, they couldn't possibly escape from due to high movement speeds.
Examples of Campaign Losses: If the party flee from orcs in an old keep's guardhouse, the orcs may be able to fortify that entrance, meaning the heroes will have to find another way in. If they flee from an adventure's villain, the villain probably escapes to become a recurring thorn in their side. Maybe the wounded monsters drink the potions of cure wounds that were supposed to be part of the treasure? Or an enraged dragon, in its fury at the party's escape, might accidentally trample some of the valuable items in its hoard. Perhaps the evil cultists finish their profane ritual and now the party must deal with the newly summoned demon reinforcing the cultists' ranks.