Diamondbacks are not slow.
They used to have a rattlesnake rodeo in Freeport, Florida.
Army Rangers from Camp Rudder on Eglin would come and demonstrate how fast they were. They would hold a balloon filled with warm air withing a couple of feet of the rattler and you could not even see the strike it was so fast.
They would also kill, skin, and clean them then batter fry in a deep kettle. The meat was white and clean looking but I just couldn’t bring myself to eat any. Others said it was very good. All you wanted for free.
I would not want to get within five snake lengths if it was coiled and hissing, no chance of catching a coiled snake ready to strike, coiled and sleeping in the cold , no problem