«فَإِنَّكَ كَاللَّيْلِ الَّذِي هُوَ مُدْرِكِي»
You are like the night that will overtake me.
«وَإِنْ خِلْتُ أَنَّ الْمُنْتَأَى عَنْكَ وَاسِعُ»
Even if I imagine that escape far from you is possible.
Ka-l-layl supplies the simile, alladhī huwa mudrikī the prospect of being overtaken, and wa-in khiltu the contrast with an imagined escape. Their several semantic functions prevent a simplistic judgment based on length alone.