It's interesting that everyone assumes the BG was stealing drugs for his own personal use (addict). It occurs to me that another possibility is that he's stealing drugs to SELL them. The street value of many narcotics makes selling them VERY profitable.
Reminds me of the old quote attributed to the famous bank robber Willie Sutton. When asked why he robbed banks, he replied, "Because that's where the money is."
Well... today the money is also in selling drugs. So, it's entirely possible that this BG wasn't driven by addiction. Rather, he had a profit motive while simultaneously placing very little value on the lives of other, and even his own. He made a fatal miscalculation.
Ah.... that's a shame.