Went into story mode to (hopefully) kill the 2 minibosses i need for the "aminishi? completed it mate" achievement: Arhat Paragon and Violet Lotus.

Went in, saw the Arhat Paragon but didn't know i couldn't reach or agro him without mage/range. Before i teleported out, i cleared to whole room (except the Sanctum Guardian). so i teleported out to get a range weapon. However, when i went back in ED1, the miniboss was gone and a lot of 'anagami' and normal arhats were back...

How is this possible?/please fix.