Sure, but first we need a full risk assessment, a flight plan that accounts for the concrete lattice, a spectrum list for the rogue signals, and a legal clearance to avoid a run-in with the city police. Mapping a subway with drones sounds fun until you realize the concrete acts like a perfect Faraday cage, the signal interference is a nightmare, and the drones will probably crash into a ventilation shaft. But if you want to play detective, start with a detailed survey and a solid backup plan.