Heres a link to the opening song of the most recent installment. If its foreshadowing whats to come, it doesn't look pretty.
The severed head on the tortoise was genius. And not too far from the truth, the Zetas recently bowled the severed heads of rival gangs into a packed disco as a message.
Heisenberg, the protagonist's street name, is based on the physicist Heisenberg, who for those that don't know, developed the Heisenberg uncertainy principle, that states that at quantum level, you can never know the true position of a particle. Great metaphor for the double life he is leading.