If for some reason a person needs to leave a mission, for example fix armor, or miss click backspace, that person loses 1 of the daily for no good reason. The game should have a way to rejoin instances like dungeons or other games do.
Ever thought of bringing a Squire? Because that’s what IMC thought you would do in their mind I’m sure.
You can re-enter the instance as long as the other members haven’t gone and finished the mission/dungeon. Simply talk to the NPC again and choose to re-enter.