Woodland mansion missing evoker

After playing a world for years (400 hours) I finally set out to find and conquer the woodland mansion. After 20+ days of in game travel I finally arrived to find the mansion full of vindicators as expected. Now that I have killed them all I cannot find the evoker, not there. I have systematically punched holes in every wall looking for a hidden room or anything indicating his location. This completely sucks as not only am I not able to log this as an achievement I can’t get the totem. Help.