Is there a way for a Hex Channeler Witch to gain access to the Displacement spell?

Is there a way for a Witch with the Hex Channeler archetype to have Displacement on her spell list?

For my purpose, I’m dealing with an NPC. I can make changes to the Witch Patron, Feats, Skills, and Archetypes (as long as she retains the Hex Channeler’s ability to channel negative energy offensively). However, I can’t change the NPC’s gear much – if the PCs kill her, they’ll get enough gear without adding a Ring of Spell Storing on top of everything else.

While I could just give a witch the spell via GM fiat, I don’t want to in this case. My players are very interested in character builds and are likely to ask how the NPC worked. Since one or more PCs might die in the fight, I’d prefer to avoid answering "it’s not really possible".