Bioimpedance varies with physical tissue characteristics. As such it can be used for real-time tissue discrimination. This has led to its application as a surgical mapping tool to differentiate between healthy and abnormal tissue intraoperatively during tumour resection. Here, we build on previous work implementing a probe-based tetrapolar bioimpedance systems demonstrator, now extracting additional information for margin analysis with imperfect bioimpedance visibility. Through finite element analysis, we show preliminary findings using a single measurement with a multiplexed tetrapolar bioimpedance probe for identifying tissue boundaries, applied to porcine tissue as a surrogate for a tumour-tissue interface.