A heat shield panel for a gas turbine engine combustor may comprise a perimetrical rail extending at least partially around a perimeter of the heat shield panel and defining a main backside cavity, a plurality of air admittance holes, each air admittance hole extending along a hole axis, and a midrail dividing the main backside cavity into a first backside cavity and a second backside cavity, wherein at least a portion of the midrail is axially offset from at least one of the hole axes.