You roll on The Perils table when you rolla 2 or 12 during a wyrd power test,
1 chances out of 6 times you check Initiative, if you fail you die outright with no other chance possible
2 chances out of 6 times you check Ld and if you fail you are possessed, if you are possesed and they send you OOA the possession ends, and I'm guessing it's a roll on the serious injuries (so, not death outright)
3 chances out of 6 you get hit at d6 strength, which is like being hit from a weapon, meaning you roll for toughness, remove one wound, and eventually roll for flesh/down/OOA, and in turn you roll on the serious injuries table.
So it's not so easy to calculate the actual chances of death without knowing the exact I, Ld and W, and even then, you might get a crippled guy from multiple injuries...