Sitting Target (1972)

Escaped convicts Harry Lomart (Oliver Reed) and Birdy Williams (Ian McShane) are lying low before they prepare to skip the country. However, Lomart can't control his rage at being cheated by his wife, Pat (Jill St. John), whilst he was inside, so he decides to kill her and her secret lover before he goes. This causes all sorts of complications to their escape plans.