What relation supports the life-preserving rationale of qiṣāṣ?

Musāwāt and Ījāz al-Qaṣr: Proportionate Wording and the Rhetoric of Qiṣāṣ

• Legal deterrence and prevention of further unlawful killing
• Imposing one punishment for every wrong
• Only from the sound similarity of words
• From the absence of any legal conditions