The expression wa-in khiltu introduces a condition. Context supplies the consequence: even imagined escape will not prevent being overtaken. But every grammatically reconstructed element is not automatically a case of rhetorical ījāz al-ḥadhf.
The issue is whether a component needed for communicating the intended meaning has been rhetorically omitted, or whether the existing construction already conveys that meaning. Mere grammatical reconstruction does not settle the stylistic classification.