Help me stat out a toxin, Succinylcholine Options

[bibliophile20]

One of my PCs is dating a chemist, and asked for something "that could kill someone and make it look natural if the ME isn't sharp or suspicious." So Amy gives the PC a vial of succinylcholine, noting that it will paralyze someone within thirty seconds to a minute, and, since their lungs will also be paralyzed, death from anoxia will follow shortly unless they have some sort of oxygen supplement or mechanical lung flow. It then degrades chemically shortly thereafter and looks like a heart attack unless the medical examiner takes a closer look.

Of course, the problem is, the toxin rules don't quite cover this sort of two stage effect, and I'm not sure what power to assign; about the only things I am sure of are:

Succinylcholine
Vector: Injection
Speed: 5+Body Combat Turns
Penetration: ???
Power: ???
Effect: Paralysis, Physical Damage

So, a little help?