وَلَكُمْ فِي الْقِصَاصِ حَيَاةٌ
And in legal retaliation there is life for you.
“Ḥayātun” is indefinite. In context its indefiniteness can highlight a weighty kind of life-preserving benefit; such an interpretation should be argued from context rather than mechanically assigned to every indefinite noun.
The expressive force lies in a concise relation between a punitive legal measure and the preservation of life. That effect is not merely a resemblance between the sounds of “qiṣāṣ” and “ḥayāt”.