The dramatic fall of the mighty Babylonian empire takes place not on a chaotic battlefield, but in the middle of a lavish royal banquet. A night of intense celebration and drinking is suddenly transformed into a moment of total destruction. The primary approach among commentators is that this prophecy points directly to the final hours of Belshazzar, the last king of Babylon. On the very night his capital was captured, he hosted a massive feast, becoming drunk on wine served in sacred vessels stolen from the Temple, only to meet his sudden end [רש״י, מצודת דוד, רד״ק, מלבי״ם, אברבנאל].
God orchestrates the exact timing and atmosphere of this downfall. He arranges for the royal feast to take place during the hot season. The heavy climate naturally drives the revelers to consume massive quantities of wine [רש״י, מצודת דוד, מצודת ציון, אברבנאל, ביאור שטיינזלץ]. A different perspective suggests that the heat mentioned is not the weather, but rather the intense passion and feverish excitement of the partygoers. God allows them to reach the peak of their celebration before instantly turning their warmth into mourning and terror [רד״ק].
Driven by the heat and the atmosphere, the Babylonians become heavily intoxicated and full of joy [מצודת ציון, אברבנאל]. However, there is a surprising alternative view regarding their reaction. Instead of joyful celebration, their drunken state transforms into violent shuddering and trembling. In this view, the revelers are suddenly gripped by the physical convulsions and spasms that take hold of a person moments before death [רד״ק].
The tragic conclusion for the revelers is a permanent, unbreakable slumber. Unlike ordinary drunkards who eventually wake up from their stupor, the intoxicated Babylonians fall into a deep sleep from which they will never rise. The excessive wine knocks them unconscious, and they are killed while completely unaware, permanently losing any future existence in the afterlife [רש״י, רד״ק, מצודת ציון]. This poetic imagery of a sudden, endless sleep specifically targets Belshazzar. He was assassinated in his bed that exact night, murdered while believing he was entirely safe and completely unprepared for his sudden end [מצודת דוד, ביאור שטיינזלץ, אברבנאל].