Introduction Bilateral lower limb injuries occur in polytrauma, yet rarely in motor car crashes with only 8.7% reported by the Australian Institute of Health and Welfare.We report a polytrauma patient who underwent delayed amputations and discuss the factors that impact the timing and decision to amputate. Case A 25-year-old driver in a high-speed rollover was ejected into stagnant water.He was shocked with mangled legs.The crash occurred remotely,delaying retrieval. CT pan scan demonstrated intra-abdominal blood,facial and rib fractures,and Gustilo type IIIC tib/fib fractures. Management Laparotomy showed torn mesentery, and traumatic herniation of the left abdominal wall. Severely contaminated limbs had mud in the intramedullary canals. Extensive debridement and lavage ensued. Rhabdomyolysis with renal failure required dialysis. Multiple debridements occurred. Cultures grew Serratia marcescens; water-borne fungi Fusarium solani; Scedosporum aurantiacum - virulent environmental fungus. Sepsis compelled BKAs, but 19 days post-admission both stumps were purulent necessitating AKAs. He subsequently recovered well. Discussion Bilateral AKAs are a devastating outcome, rare in civilians. The decision to amputate is complex, involving interdisciplinary teams. Factors including soft tissue and bone viability, vascular supply, neurological integrity, and likelihood of functional limbs impact the decision and amputation level. Our case illustrates another critical factor. Despite adequate debridement and antimicrobial treatment, the impact into water drove bacteria and fungi deep into bony medulla and interfascial planes, precluding eradication. Infection should be considered in patients with ongoing sepsis, even if tissue appears healthy.