Causing pain for fun and profit.

With the exception of the lucky bastard who dies in a nuclear flash; every person on the planet dies of one single cause. Cerebral hypoxia. That is the cause of death. The mechanism of death is what induces this - Now, this may be due to cyanide oxyphilia, organophosphate paralysis of the lungs; simple heart failure, exsanguination, or simple gunshot wounds. After you've done it a few times; this bit gets boring; because the ending is predictable. Cerebral hypoxia, every time.

So liven things up a bit while you can. Finish them off precisely and definitively; personally I prefer either ligature strangulation with a loop of fencing wire and a couple of dowels, or intravenous administration of pancuronium bromide, potassium iodide and sodium thiopental... But before you get to that stage, stimulate the nerve endings a bit. Let 'em know they're still alive. If you're interesterd in information from them directly; you don't want to get too enthusiastic - After a certain pain threshold the memory distorts, common sense fails and panic reacions dominate. It's impossible to get a straight answer. In this case, it's as simple as implementing a 'pain proxy' - Loved one or relative, you work on them while the initial subject watches and listens until they're ready to talk.

Highly encouraging results have been achieved with a benzocaine local anaesthetic, and then abriding the skull very carefully with a dremel or similar rotary trepanning tool until the cerebellum has been exposed and adding dropwise liquid nitrogen to specific motor centres.

Similarly; a cauterising microwire probe, threaded into the lymph nodes under the jaw and triggerred elicits a fascinating histamine response which can induce instant allergic reactions; suffocation, sweating, anxiety...

I'm quite partial to an IV bag of sodium lactate, of sufficient concentration; wherein for as long as it is hooked into the subject's mainline they will be in a pronounced state of pure, abject terror. I have seen men rip open their wrists wih their teeth, preferring death to the indescribable fear they were experiencing.

There are more conventional means, such as fibreglass slivers under the fingernails, suspensions of uric acid injected into the joints, carbon dioxide aspirator masks, magnetostriction coils... none of which leave any physical evidence but are thoroughly capable of causing indescribable pain...

Oh, and for those special someones... cultured extract of the australian platypus' crural gland, prepped into a glucose/agar medium...