The doctor stopped the fight, and if the doc seen the hand or Bowels showing it to his conner that would of been a good reason to take a closer look. Fabor and Cruz the doc didn't see it to stop it. There's a lot of if's for a concret answer on this. Not to down play someone who broke their hand before doesn't mean it was anything like theirs.
Plus Bowels was already down on score and with his bread and butter offense not working right may well of been the smartest thing he could of done.