Killing Bottle

I am trying to find out the meaning/origin of the following phrases from Stephen King's book the Green Mile:

dead run
in a walk
riding the rods
lickety-larrup
killing bottle

a "dead run" is an all-out full speed run

And if you run at a dead run and get a big enough lead in a race, sometimes you can approach the finish line and not even have to run to seal the victory: you win in a walk.

Riding the rods (or rails) is a means of transportation that hoboes used (and may still use, as far as I know) riding on the undercarriage of rail cars. It is, of course, dangerous and illegal... but thrifty.

A "killing bottle" is an entomological apparatus into which an insect falls and dies.
The bottle used to be filled with very toxic poisons but is now filled with nail polish remover. The insect is caught in a net and is put into the killing bottle and then into a specimen box and onto a spreading board to be shown or observed.