I think death would be too easy for Walt. He's expecting to die and he seems perfectly fine with it. Jail time would be a killer.
Although production added like a billion more flowers than what one or two lily of the valley plants would normally produce, I recognized it in the scene when Walt was spinning the gun and I remember thinking, Why a lily of the valley? It's a spring-blooming plant, mostly suited to wooded and shady areas. I couldn't understand why Walt would have it in his austere New Mexico back yard. At the time I just chalked it up to someone in set decoration not knowing much about plants, but then of course as soon as Jesse said that Brock was poisoned by lily of the valley, I figured it out.
Also particularly evil of Walt was when he had to go back home for something but he wasn't sure if there was a bomb rigged or men staking out his house (which there were), so he fucking calls his old lady neighbor to go in and check to see if he left a burner on while they were "on vacation". UGH. The woman's cane was a nice touch, too.