Environmental criminology and urban planning literature acknowledge the link between neighborhood permeability and crime patterns, yet consensus eludes discussions about the precise impacts of population mobility. In this study, we enhance permeability measurement by detailing the direction of population flow through fine-scale mobility data analysis on the census tract level for outflow and inflow measurements. We collect and analyze the relationship between mobility flow and crime incidents, including aggravated assault, burglary, motor vehicle theft, and robbery in Houston during 2019. Our findings indicate a positive correlation between population outflow and inflow and all crime types examined while controlling for other factors. Notably, the effect of population outflow surpasses that of population inflow across all crime models. In line with existing literature, we observe a positive association between concentrated socioeconomic disadvantage, residential instability, and crime risk in the study area. Drawing on insights from environmental criminology theories, especially routine activity theory and social disorganization theory, this study contributes to the existing literature by enhancing the measurement of travel mobility and its directions under community permeability. The results provide insight into how population mobility influences crime resilience with fine-scale geographic patterns. The findings underscore the importance of distinguishing between direction-specific measurements when considering environmental permeability within crime-place research models.