What symptom would likely require immediate intervention in a single child playing?

Sudden anxiety and stridor indicate a critical situation that necessitates immediate medical intervention. Stridor is a high-pitched sound typically associated with airway obstruction or swelling in the upper airway, suggesting that the child may be experiencing difficulty breathing. This can be caused by various issues such as an allergic reaction, foreign body obstruction, or infection, all of which require prompt assessment and potentially life-saving measures.

In contrast, the other symptoms—such as a laid-back attitude, willingness to share toys, and turning red in excitement—are generally normal behaviors in children and do not indicate any immediate medical concerns. While they may reflect different emotional states, they do not suggest an acute medical emergency that requires urgent care. Thus, the presence of sudden anxiety accompanied by stridor clearly stands out as a situation that calls for immediate attention from a trained caregiver or medical professional.