Sounds doable, but that pump’s shell is a rust trap—any coolant fluid will be a chemical cocktail. I can sketch a crude filter plate off the old conduit map, but you’ll need to line the tank with a charcoal bed and a mesh screen to catch the grit. Just remember: if the pump leaks, you’re bleeding the tunnel’s own water. I’ll send you the schematic over three separate files—no one central server ever knew what they were saving. Let me know if you need the exact routing to keep the flow from back‑flooding the ventilation shafts.