Knives: Some Deadlier than Others

So here I'll try to post up and discuss some of what these things would be well suited for. What am I talking about? Special knives: the WASP Injection Knife, the old Soviet Spring Knife and lesser known NSR-2 ballistic knife), and the Chinese Type-85 Bayonet Pistol.

Question: So the WASP Injection Knife? What is it, what does it do? And does it matter?
 Answer: Yes. Its a knife that injects pressurized CO2 into the wound (from a CO2 cartridge) through a channel in the blade. And you tell me. Look:

That's a kill, considering a 'melon acts much like a human torso (sans organs and bones and elasticity).

Question: How does it work?
Answer:

Question: Wow. Stats?
Answer: As a standard Knife, but with the following. If you succeed on the attack, you can depress the trigger to deal an additional 2d10+2 (think about "poofing" a freezing ball of CO2 gas in a wound the size of a basketball!) damage that ignores armor (even natural armor) that is added to the damage of the stab. The CO2 cartridge is good for two activations before taking one full round to replace. $500 USD (real price).

Then we come to the Soviet "spring knife". I couldn't find its old designation so its "spring knife."

First made (fairly) widely popular in media on a show called Deadliest Warrior. There's not much to say other than it acts as a knife except with shot (single shot obviously) it deals 2d4 damage at AP1 with a range of 4/8/16. It takes an action to reload it if the operator has a spare blade. Obviously silent unless you miss. Unknown cost.

Now we have the more useful Tula NRS-2 Ballistic Knife. What's special about it? Its a knife that has a gun in the hilt. It's a scout knife and is completely silent (the round uses pistons to trap the firing gases and launch the bullet out).

So that's all well and good, but how is it used? Like this:

Bad. Ass. It even has iron sights.

So as a knife, its a knife, like all the rest. As a gun it is 5/10/20; 2d6-1; ROF1, 1 shot; Silent, Reload 1. It uses an AK-47 bullet but looks like the person was shot at about 300m instead of point blank (no firing gasses or muzzle flash and minimal recoil). It was designed in the '80s and is still in use. Enough proof for me.

Now the weirdest one. The Norinco Type-85 Bayonet Pistol.

Chinese. '80s. 4 shots of .22LR. The "barrels" are partially in the blade surface.

Stats: 3/6/12; 2d4; ROF1; 4 shots. It has iron sights and takes a round to reload.

Overview: So these things are pretty bad ranged weapons, right? Maybe. But their real advantage is this (aside from the WASP): your opponent brought a knife, and he thinks its a knife fight now. WRONG. You brought a knife-shaped-gun to a knife fight. Boom (literally... well, bang/pop at least).

For the WASP, the first time you stab some poor sod and his chest explodes (silently I might add, well the CO2 at least not so much the chest rupture...) his friends might be more inclined to surrender. Fear is an advantage.