.. I have some experience editing audio in pro tools so I could just hack away at the actual audio region to get what I want. My only question is how do I export the wav file of the source drum file at my selected tempo?
Pro Tools should have a clip properties to set the source tempo of the clip to 250 then it will adjust to the 248 project tempo.
You can also set a new Pro Tools session to 250 bpm,
import the 250 bpm drum file from the Real Drums folder then set the Pro Tools to 248 bpm and the drum file should adjust,
now you can drop the 248 bpm drum file from Biab and edit the section you don't like by adding sections from the Real Drums source clip.
Just make sure you render the drum track dry, flat and center with DROP +
MIDI is another option, if you drop the track to DROP MID.