Dermatology — Necrotizing Fasciitis Pain Out of Proportion + Crepitus + Bullae

A 42-year-old diabetic male presents to the emergency department 36 hours after a minor laceration to his right leg. He reports severe pain disproportionate to the wound size, with rapid swelling and systemic toxicity (fever 39.2°C, HR 118, BP 95/60). On examination, the skin shows ill-defined erythema with surrounding edema, palpable crepitus, and dusky violaceous discoloration. The structure marked **D** in the diagram—hemorrhagic bullae with skin anesthesia—is observed overlying the affected area. Which of the following is the most critical immediate management step that directly determines survival in this clinical scenario?