"Pilot"
Season 1, Episode 1

In Walter White's pre-Heisenberg life, when things could go wrong, they went wrong fast. Cancer, horrible job, selling off his ownership of what would become a billion dollar company. So, naturally, his first steps into the drug game were rocky. In the series' first episode, Walt is held hostage in the Winnebago by Emilio and Krazy-8, while Jesse is knocked unconscious nearby. The dealers are on the verge of killing Walt, until he makes a deal: he'll show them how to cook his meth, in return for sparing his life.

But, as what has remained a theme throughout Breaking Bad, things aren't always as they seem. Instead of showing Krazy-8 and Emilio how to cook crystal, Walt thinks of the fly and mixes chemicals he has with him to create phosphine, a poisonous gas, and locks the two inside the RV to let them suffocate to death. 

Or do they?