A 55-year-old male presents to the emergency department with epigastric pain 12 hours post-alcohol consumption, followed by vomiting fresh red blood (200ml). Physical exam: soft abdomen, tenderness in the upper abdomen, liver not palpable, spleen palpable 1.5 cm below the costal margin, normal blood pressure (BP). In the ER, the patient develops persistent hematemesis, restlessness, and cold sweats. The most urgent management at this stage should be: