Thanks for all your replies guys! I posted it elsewhere, and someone had the gall to go "It's not even his job" because it was "commercial vehicle enforcement".
If you are a cop you have a duty to protect and serve. I saw the guy in the cruiser, it was an officer. He should have stopped. His reply "oh, I'll go back," was one of "I was either oblivious to the situation or I was trying to get away with not doing my sworn duties,"
Even though traffic was backing up, it only takes a few cars moving over and one not paying attention to create a huge accident.