فلما احسوا باسنا اذا هم منها يركضون

فَلَمَّآ أَحَسُّوا۟ بَأْسَنَآ إِذَا هُم مِّنْهَا يَرْكُضُونَ

This verse invokes a sense of fear and awe of Allah's might and power for me. Allowing the disbeliever to run, even momentarily, creating the illusion of escape, is a form of psychological torture. To say nothing of the terror they'll know when they realize they are yet to experience Hellfire. 

I think It adds a shade of depth to Allah's mention of giving respite to the criminals before seizing them, portraying the respite as a fleeting moment of running before destruction.

It is indeed a powerful ayah and evokes a sense of fear and awe of Allah's power. They didn't even see Allah's punishment but they just 'sensed' it or 'perceived' it, and that made them go running. Subhanallah. Jazakallahu khair for sharing this. 

Reflections on Surah Al-Anbiya Ayah 12