After all of Walt’s internal battling, pros and cons listing and indecision, he murdered Krazy-8, cleaned it (and him to such pristine perfection that you almost didn’t know Krazy-8 was even there, then went home to his wife and told her he has lung cancer.
We don’t see a lot of internal struggle on Walt’s part after this first murder of his. It’s nothing like what we will see a few seasons later when Jesse kills someone. Of course, the person Jesse kills is more innocent than Krazy-8, so there’s that, but I also think that internally, even just going into this whole business endeavor together, Walt and Jesse are two very different people, with different moral compasses, tendencies to violence, and all that.
April Julia 