The article describes the case of a 50-year-old woman with multiple injuries who received general anesthesia with remimazolam and after administration of 0.4 mg of flumazenil recovered briefly, but then fell unconscious again for 75 minutes. Re-sedation was diagnosed after excluding other causes and confirmed by simulation of anesthetic concentration using TIVA software. Remimazolam with flumazenil may shorten recovery, but re-sedation puts the patient at risk. Reasons include individual differences in remimazolam concentration at the site of action and rapid tolerance, not just administration of flumazenil. In practice, flumazenil should be administered with caution, avoiding a high single dose and considering delayed administration. Re-sedation must be carefully monitored in critically ill patients. Further research is needed on the optimal timing of flumazenil administration and the characteristics of at-risk patients.