The interrogation at the beginning
I've always felt the 3 best ways to get information (or torture) someone would be:
1) Inject someone with heroin a few/several times a day for a month; make them go through withdrawals with the promise of relief for what you want to know.
2) Fire. Burn an inch of their neck or chest, just with a lighter. If they don't talk, burn the next inch.
3) Induce a grand mal seizure, medicinally and slowly. Give them some counteractive meds, then promise to do it again.
In The Jackal, they were short on time, so 2 and 3 would probably be the most effective, I think.. Just my 2 cents.
(I'm an epileptic, so the last would be the worst imo.)
"I do not like mixing up moralities and mathematics."
Churchill