Remember that alhough Chalana Arroy drives her worshippers to heal anyone who needs it, which means, yes, they may decide it is necessary that they heal a warrior from an enemy clan before attending to members of their own clan, they are not going to be happy if the Enemy warrior leaps up from his sick bed and starts laying about him with his sword.
In the heat of battle our warriors may regret that the healer has helped an enemy live to fight another day, but cooler heads, on reflection may be glad that a bloodfeud, or claim for a thanes weregild has been avoided