Building Optimal Pressure Damage

In MMO terminology, there are two types of damage - pressure and spike.  Pressure damage is ongoing damage that is concerning, but not particularly fatal given basic precautions are taken and players don't play sloppily.  Spike damage, on the other hand, requires an attempt at active mitigation.  Spike damage translates to tabletop games fairly easily, but pressure damage doesn't particularly work in a straightforward environment across the board -- especially in Shadowrun.

    Your average character has 3 Body and around 3 armor, which leaves around a 70% chance that the runner will shrug off 2 damage with each incoming attack per turn.  3 damage per attack therefore should be our threshold to make things “interesting,” with a 32% chance that it is completely soaked, a 33% chance that 1 damage makes through, and a 26% chance of the character taking 2, with nearly 0 chance of 3+ damage coming in.
     Let’s look at the armor pools of a character that I have a very difficult time challenging in a fight.  5 Body/12 Ballistic +6 if using a shield.  How do I bring him down to scale?  The obvious answer is stun damage or something ignores armor entirely, as he has more than a 60% chance at soaking 6 without a problem, and the shield gives him more than 60% at soaking 8.  I’d need to run 9 damage quickly, or give every mook I want to be taken even remotely seriously a way to generate either stunning or armor-ignoring damage.
     The difficulty with stun damage is that there is no current easily available use to NPCs that aren't geared to the gills with milspec things.  However, flipping through Arsenal, I see something with significant potential – a crowd control toxin called Breathtaker, which deals 8S and has a KO effect if unsoaked damage exceeds Willpower.  That reminds me of a high-powered pepper spray.  So what if there were a readily available civilian derivative?   Breathtaker has a 27% chance of dealing 2s, 27% chance of dealing 3s, and only a 26% chance of dealing above 3s.  We’d need a way to challenge players with a 6-dice pool without gibbing a player with a 3-dice pool. That 2-3 damage range is what we’re looking for, as it’s enough that even a Willpower 6 character won’t easily be able to soak it (31% chance).  However, it’s got a pretty meaty chance of hitting the low-WP character pretty hard, and after 3 shots would reliably down him due to its KO effect.
     Let’s drop it to 7S.  Suddenly, there’s only around an 18% chance of exceeding 3 damage, while maintaining only a 27% chance of not hitting the 2S threshold.  Drop the KO effect and turn it into a recurring effect, and BAM – easy pressure damage that at least becomes a nagging worry of characters.  Now one lucky hit turns a nameless mook into a mild challenge.  So let’s flesh this sucker out.

SuckerPunch – 7s, Recurring until fully soaked.  100 Nuyen, 1 dose.  A pressurized spray commonly available at drug stores, SuckerPunch is a civilian derivative of police-grade Breathtaker, a riot-control inhalant.

Suddenly, we've created a civilian-accessible form of pressure damage that hits (most) runners equally without being fully debilitating.  As a bonus, the Arsenal version, Breathtaker, makes a great spike damage effect due to its KO properties and only slightly higher damage.