Quick Question

So picked up the full trilogy a month or so ago and I'm currently on Book 3, something that really confuses me though is how coldbloods exactly are made; its stated that they come from when coldbloods kill humans, and that you can't really be sure if they'll turn.

Does it matter how they're killed by the coldblood? Does being cut to ribbons by a Voss highblood or having your heart ripped out by a Dyvok have the same chance as being sucked dry by a mediae or clawed to death by foulbloods or hell, if a Voss mediae uses cannon to kill people can they turn (like the coldbloods in the sea that Celene noticed)? Also how did Kiara "claim" Aaron if it's unclear if he would turn or not, does fully sucking their blood cause them to turn 100% of the time or not?