For me, this statement says that Penny's choke hold either contributed to or directly killed Neely. The question should not be if Penny's action contributed to the death of Neely. The question should be whether Penny was acting to protect passengers on the train from an erratic dangerous person - and were his actions purposely excessive?
Penny was trying to incapacitate a dangerous individual. How was Penny to know Neely's medical condition(s), which contributed to his death.
The dead guy’s biggest mistake was not crying “I can’t breathe.” If only he’d learned to read the news.