Repeat after me: you will not let the Witch to live just because she's now cute and appealing and doesn't sound like a crackwhore. The Emperor for sure would not approve weakness regarding waifs with psychic powers.
Also, the Forgefiend fight. I'm he only one that finds kind of weird how the fights
before require some good planning (the combo of HP-giving speakers, dumb but hard-hitting servitors and assorted mad Mechanicus are fun to fight) but the Forgefiend itself is kind of... trivial? You spam abilities and it dies in 2-3 turns, for sure it counters but you are never in danger of
really losing control. It's weird how the chaff fights are harder, or maybe it's just me.