Diffraction data were obtained from one large lysozyme crystal soaked with 50 mM 4-aminosalicylic acid (PAS) and 50 mM 3-aminophenol (3AP) for 15 min prior to cryo-cooling. Diffraction data were obtained from five regions located near the crystal surface, in 10 µm shells (top left). Diffraction data were also obtained from the center of the crystal (top right). The observed occupancy from the near-surface shells was 90%, 70%, 50%, 30% and 10%, respectively (bottom). The observed occupancy from the center of the crystal was near zero (<5%).