The abrupt end to a drunken feast, replaced by a terrifying, unreadable message written by a mysterious hand, throws the royal palace into complete chaos [ביאור שטיינזלץ]. The king experiences an overwhelming wave of terror and panic [רש״י, מצודת דוד]. While his initial fright was noted previously, his anxiety now reaches a new peak, causing the color to drain from his face even more drastically than before [מלבי״ם, מצודת דוד].
This sudden escalation in dread stems from several realizations. First, the complete failure of his wise men to decipher the writing destroys any hope of understanding the mystery [יוסף אבן יחיא, אלשיך]. Second, their inability to help proves that the message does not come from lesser spirits or demons, which Babylonian magicians could easily manage with spells. Instead, it is a direct message from God [מלבי״ם]. Finally, a clear warning from heaven usually gives a person a chance to repent or prepare for the worst. A completely hidden message, however, is not a warning at all; it is a declaration of inescapable, absolute doom [מלבי״ם, אלשיך].
Surrounding the king, the royal officers and nobles fall into deep confusion. The primary approach among commentators is that they suffer from mental disorientation and anxiety, acting like people who have completely lost their wits and have no idea what to do [אבן עזרא, מצודת ציון, מלבי״ם]. They run about in a rushed and panicked state [רש״י].
Providing a unique perspective, [אלשיך] highlights a sharp contrast between the reaction of the king and that of his officers. The king feels the bitter truth deep within his heart and cannot deceive himself. The officers, however, knowing they are not the direct targets of this impending disaster, respond by offering false interpretations and empty words of comfort in an attempt to please the king and lift his spirits. Yet, with his heart burning with pure terror, the king remains entirely unable to accept their hollow reassurances.