Many of the most fundamental questions in microbiology - how pathogens interact with their hosts, how cells respond to stress, and how phenotypic diversity arises within clonal populations - cannot be answered through bulk measurements alone. Population-averaged analyses mask the molecular heterogeneity that drives infection, resistance, and adaptation. To uncover these mechanisms, we need approaches that can spatially resolve molecular heterogeneity at the level of individual cells and their subcellular compartments. The SEISMIC research facility is developing and applying technologies that make this possible. By combining live-cell imaging, targeted nanocapillary sampling, and high-sensitivity mass spectrometry, we can visualise and extract single living cells or defined subcellular structures (e.g. mitochondria, nucleoli, stress granules) for downstream omics analysis. In principle, this workflow allows profiling of metabolites, lipids, and proteins from precise cellular regions. This approach is being used to characterise the protein composition of stress granules in U2OS cells under arsenate-induced stress. Analysis of whole-cell and stress granule samples revealed a distinct set of proteins enriched in stress granules but absent from controls. Functional enrichment analysis indicated strong representation of pathways linked to mitochondrial gene expression, translation, and RNA metabolism. Alongside known stress granule proteins, many additional novel candidates were identified with potential roles in stress adaptation. This highlights the potential of subcellular proteomics to uncover new molecular players in stress granule biology and cellular stress responses.