It being the Paladin does not make sense to me storytellingwise. Being the obvious choice to me makes it the least likely choice.
Remember the Paladin is a person with a knightly personality of honor. Also remember she is a subordinate not a guild leader. She probably sworn loyalty to her leader and to act against their lord is worse than any dishonorable act their leader does. I believe the leader of her guild is the traitor and is going to force her to take the attention of that role. Or it is going to be someone she has sworn not to betray. Her skill gave her classic diversion bait.