I'm not sure...I do know that Bodhi at one point will flee into a little chamber on that same floor, and it's only there that you can kill her and the vampire thing takes place. Maybe if you have her surrounded she cannot flee and therefore you are stuck...try and see if she flees if you give her the chance.
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Melusine, Archbabe of the OHF and the LH
Your voice is ambrosia