(at around 35 mins) When Korsak is holding the purse open, his hands change positions between shots. Then, after he lifts the purse by the straps and sets it back down, he lets go of the straps and lays his hands on top of the purse, but in the next shot he is holding the purse straps up again.
When they are in the lab Dr. Isles explains that a neuro-toxin killed the victim by "causing paralysis to the voluntary muscles", to which Rizzoli says, "so he couldn't breathe". Voluntary muscle actions are what a person controls, like leg or arm movement. The heart and lungs are part of the involuntary muscles. Unless the script contained the wrong word, and no one caught it, one assumes Sascha Alexander simply used the wrong word.