That's it, I didn't study it, just have read about it
You could argue that following orders to kill is provocation, and thus fits the original question.
( Labia Majora You keep on talking but it makes no sense at all, Tue 17 Aug 2010, 11:48, 1 reply, 16 years ago)

Only if you didn't know what the word 'provocation' meant.

( WormuIus, Tue 17 Aug 2010, 11:49, Reply)

Apologies
I wrongly assumed you could provoke someone else to do something to a third party, rather than provocation being a strict two-party affair (victim provoking assailant).
( Labia Majora You keep on talking but it makes no sense at all, Tue 17 Aug 2010, 11:52, Reply)

it is possible to have 3rd party provocation
but Wormulus is still right, they weren't provoked to kill, merely encouraged
( Amberl was stripey and dominated Europe, Tue 17 Aug 2010, 11:53, Reply)

Would encouragement become provocation
If there was a penalty for not going through with the task? (and assuming no prize for doing it)
( Labia Majora You keep on talking but it makes no sense at all, Tue 17 Aug 2010, 11:54, Reply)

no
it might become coercion (though coercion is not a defense as it happens for murder) but it's still not provocation
( Amberl was stripey and dominated Europe, Tue 17 Aug 2010, 11:56, Reply)

Gotcha, thanks :)

( Labia Majora You keep on talking but it makes no sense at all, Tue 17 Aug 2010, 11:56, Reply)

If the penalty was serious harm to you or to people personally know to you or you or their property
then you can offer a defence of duress to certain crimes. Not an unlawful killing though.
( WormuIus, Tue 17 Aug 2010, 11:57, Reply)