Imitation learning for mobile manipulation is a key challenge in the field of robotic manipulation. However, current mobile manipulation frameworks typically decouple navigation and manipulation, executing manipulation only after reaching a certain location. This can lead to performance degradation when navigation is imprecise, especially due to misalignment in approach angles. To enable a mobile manipulator to perform the same task from diverse orientations, an essential capability for building general-purpose robotic models, we propose an object-centric method based on SAM2, a foundation model towards solving promptable visual segmentation in images, which incorporates manipulation orientation information into our model. Our approach enables consistent understanding of the same task from different orientations. We deploy the model on a custom-built mobile manipulator and evaluate it on a pick-and-place task under varied orientation angles. Compared to Action Chunking Transformer, our model maintains superior generalization when trained with demonstrations from varied approach angles. This work significantly enhances the generalization and robustness of imitation learning-based mobile manipulation systems.