This time Kendall almost had what he wanted. He was one day away from what he would define as "saving the company." While whether that is the case is up for debate, it is undeniable that his urge to satisfy his cocaine addiction pushed him to act an of self-sabotage beyond reason. He followed a guy from the catering service who had just been fired and was high to get cocaine in the middle of the night, proposing to drive while he knew he didn't drive that often. It ended up in a car crash. His father got wind of it and handled it by putting Kendall in a checkmate position.
From the beginning, Kendall has always wanted to prove himself, show the world that he was up to the game and not just a spoiled heir who inherited his father's empire. However, he struggles a lot with his self-confidence to the point of not even being able to express himself correctly on multiple occasions. His insecurity often turns into some sort of mania resulting in irrational behavior and sometimes just plain self-sabotage.
There is a fine line between becoming someone great, the person you ought to be (i.e. achieving your full potential), and being a distant shade of that person. Staying above this line involves avoiding self-sabotaging behavior, in this case, drug addiction. There is nothing sadder than being the author and perpetrator of one's demise.
“Someone once told me the definition of hell; on your last day on earth, the person you could have become will meet the person you became."
— Anonymous