1) Some spells like Death Wish, when cast by an out-of-combat character upon an in-combat character, pull the out-of-combat character into combat. Other spells like Fortify, Armour of Frost, Living on the Edge, and probably others do not pull a character into combat when they are cast on a character in combat. This means a player can leave a character with these latter skills far away from the fight, out of combat, and the out of combat character can endlessly recast these buffs on the characters who are in combat, trivializing any fight with relatively free positioning.
2) By using one ability, then moving far away from combat with their remaining action points, characters are automatically removed from combat, allowing them to move back into combat to take another turn. Players can repeat this pattern to take infinite turns. As noted
here the Escapist talent can be used to perform a similar exploit.