How to find potential issues in damage macbook pro
" It booted, but the fans blew at full speed and it shut itself off while still running firmware."

This may be unrelated to the water damage. It is very common with high spec laptops that the fans get filled up with fluff and then overheat. It is a good idea to open up your laptop once in a while and hoover out the fluff. Or wipe it away with a clean, dry toothbrush. This is a problem I often had with a laptop that I had with coolers, fans and a high end graphics card a few years back.
You can tell if it struggling if you hear the fans running a lot, and the base of the computer gets hot. Cleaning out the fans can give your laptop a new lease of life.