i dont think it works like that. Anything below sixty percent is basically death, but above that the guy might live with bad effects.
Every time a Halcyon user uses his ability, he rolls to see if he triggered the effect which is under the % number. If the effect is 5%, the trigger has to be below a five on 2d10s. So if Mammal Man triggers his fur of protection, he would roll a percentage to see if the effect is activated. Anything above five is no effect. Anything below a five, you go to the chart and roll for side effects. Anything below Sixty is death where the villain blows up, catches fire, turns to acid and dissolves, or drops dead. Anything above a 60, you can temporarily lose powers, get an insanity, then get powers back, turn into a vegetable up to 60 months, but then awaken at full power, partial power loss and brain damage, and then total power loss and brain damage.
now if someone uses it twice, there is an 80 chance he will die. So if Mammal Man is injected once, then is injected again and rolls 81 or better, he gets a power and a side effect like a physical disad. Also his chances of blowing up are 10% every time he uses an ability.
if mammal man goes back a third time, he rolls the 80 to see if he dies then he rolls on the chart. Anything below 20 is death, then sickness with all of his powers and attributes halved, then he switches powers, then one percent 99-00 gets a major ability and becomes a mega with the minor abilities and achilles heel. But he can also blow himself up with a 15%
how these dice rolls would work in Champions I don't know, but i assume it would be a conditional side effect built in the power, with a percent applied to the charts for what happens.
CES