I decided to go back and review your previous logline attempts:
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“When a school is held captive by the man responsible for the death of his sister, a doctor has visions of a lost childhood revealing the secret between his sister and the man that now threatens his daughter’s life.”
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“With an entire school held captive, a doctor must relive a traumatic childhood that may solve the mystery behind the sadistic madman that threatens his daughter’s life.”
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“A doctor is forced to relive his traumatic childhood in order to solve the mystery that may save his daughter’s life.”
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The problem is you are presenting some abstract ideas that don’t really give us any clue to what’s going on.

I would start with the best part of your loglines: “When his daughters school is held captive by the man responsible for his sisters death…” (This is very solid)

The problem is, “Saving his daughter by reliving a traumatic childhood” or “saving his daughter by battling his fear of needles,” is way too abstract, it doesn’t tell us how does that action saves his daughter.

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“When his daughters school is held captive by the man responsible for his sisters death, In order to save her, a father must give clues to the police negotiator about madman’s mindset by undergoing hypno-therapy, reliving a traumatic experience”
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This would explain how reliving a traumatic experience would help save his daughter.

However, my logline attempt is still too long and rough but hopefully you see where I am going with it. I hope this helps.