A couple of issues:
Separating the scripts is quite difficult because the code needs to store a lot of session information to interact with the Mooshimeter. What is it you are trying to accomplish? You might be better served by modifying the script to respond to actions from the user through some other means.
Regarding notifyCB: notifyCB is a callback, which is called from an inner layer of the bluetooth stack when the update is received over bluetooth. BGWrapper.idle() constantly serves the bluetooth stack and will call notifyCB when something is received.
If your code is on Github I can probably be more specific. Hope this helps! Best