A 52-year-old man from Delhi presents with acute epigastric pain radiating to the back, accompanied by nausea and vomiting for 6 hours. He has a 15-year history of alcohol abuse. On examination, he is febrile (38.5°C) and has epigastric tenderness with guarding. Serum amylase is 1200 U/L (normal <100), lipase 950 U/L, and transaminases are mildly elevated. Abdominal ultrasound shows a dilated pancreatic duct (4 mm) with hypoechoic parenchyma. Which of the following best explains the pathophysiology of elevated pancreatic enzyme secretion in this patient?