Obstetric USG — Placental Abruption Retroplacental

A 28-year-old G2P1 woman at 32 weeks gestation presents with acute onset of severe lower abdominal pain and vaginal bleeding following a motor vehicle accident. On examination, she is tachycardic (HR 118/min), hypotensive (BP 92/58 mmHg), with a rigid, tender uterus. Fetal heart rate monitoring shows variable decelerations and bradycardia. Obstetric ultrasound reveals a retroplacental hypoechoic collection and thickened placenta. The structure marked **D** in the diagram shows fetal cardiac activity with abnormal heart rate patterns. What is the most appropriate immediate management step for this patient?