The trial judge was right in having the common-law defence of duress go to the jury.
R. v. Lavallée  1 S.C.R. 852
Accused was a battered woman who killed her common-law partner one night as he left her room. She used a psychiatric assessment to support her defence of self-defence. Lavallée was acquitted at trial but the Man. C.A. ordered a new trial.
Is it inherently unreasonable to apprehend death or grievous bodily harm unless and until the physical assault is actually in progress?
No. Appeal allowed; acquittal restored.
Where evidence exists that an accused is in a battering relationship, expert testimony can assist the jury in determining whether the accused had a “reasonable” apprehension of death when she acted by explaining the heightened sensitivity of a battered woman to her partner’s acts.
In her judgment, Wilson J. analogizes the battered wife syndrome to the “traumatic bond” that occurs between hostages and captors, concentration camp prisoners and guards, etc. (theory of “learned helplessness”)
Academics have seriously criticized the view that the Court adopts because it medicalizes the problem and discounts the voice of the particular woman. The detractors have said that Court’s view creates a false dichotomy between a woman who is either reasonable “like a man” or reasonable “like a battered woman.”
R. v. Petel  1 S.C.R. 3
Petel shot the daughter’s abusive and drug dealing boyfriend and his friend one evening. During the previous months, the boyfriend kept selling drugs out Petel’s home and beating her daughter. On the night in question, the boyfriend came over to the house and forced Petel to hide a gun and weigh some drugs under threats. The daughter then came home with the deceased. Petel took the gun and shot both the boyfriend and the friend. She was convicted of second degree murder. The trial judge instructed the jury that the threat or act giving rise to self defence had to occur that evening.
Did the judge err in his answering the jury’s question?
Yes. Crown’s appeal dismissed; Affirm Qc C.A. order for a new trial.