well i first tried to test using a voltage from a power supply, and at 0.3v or something it was drawing like 400mA at which point i thought it was a good idea to turn it off
the potentiometer was not working as a voltage divider because all of the voltage was between GND and the input no matter where the brush was, which would happen when all the current was flowing through that half of the divider (i.e. brush shorted to 5V). The point at which the voltage on the pin stopped being 5V was right at the end of the pot, meaning only when the resistance between gnd and the pin was tiny so a large amount of current was flowing would it drop (small resistance through exploded ESD diode)