The bathroom scene in Breaking Bad where Hank realizes that Walter is Heisenberg is one of the most powerful and pivotal scenes of the entire show, and there are a few reasons as to why this location was chosen. Firstly, bathrooms are typically a place of solitude and reflection. In storytelling, they can function as a private space where external distractions cease, and a character is given a moment of silence to think or discover something crucial. It's an intimate, personal space that heightens the drama of a revealing moment. Secondly, the bathroom scene has a symbolic essence as well. Reading Walt Whitman’s poem inscribed in Gale's book while using the restroom brings the disgusting realities of what Walter has been doing back into the stark, sterile environment of normal domestic life, highlighting how these two worlds have catastrophically clashed. Also, there is a sense of dramatic irony in this scene. The audience is aware of Walter's secret for a long time, and the bathroom breakthrough gives the unsuspecting Hank a sudden jolt towards the truth. Lastly, the bathroom location was also probably chosen to show Hank as vulnerable. He’s not in his element at the DEA office, armed with resources and support. He's alone, in his most private space, stumbling upon a revelation about someone he considered family. In conclusion, the bathroom scene is crafted meticulously to create a drama-infused, ironic, symbolic, and solitary environment for Hank's critical realization about Walter. It's part of the genius of the show's storytelling and the placement enhances the shocking gravity of the revelation.