«وَلَمْ يَبْقَ إِلَّا التَّهْوِيمُ»
Nothing remained but a state of drowsiness.
Tahwīm is light dozing, not deep sleep. The narration also stresses how dark the night has become, joining physical darkness to the gathering's fatigue.
This makes the interruption dramatically effective. The listeners are close to drifting off when a sudden sound comes from outside.