Hello,

Today I experienced a fly away and the spark did not respond to commands from the RC. Lucky I was inside and it fell in the room.

I am now having to do an IMU calibration

Sorry to hear about this, does the drone hurt by the crash, please take attention about the battery compartment of the drone and check if it has any broken parts.
Besides, I would recommend that you sync the flight records and export the flight log, then contact the support to open a case, we'll submit a data analysis to find out the cause.  http://www.dji.com/support