First. Unlawful aggression; Second. Reasonable necessity of the means employed to prevent or repel it; Third. Lack of sufficient provocation on the part of the person defending himself." Unlawful aggression is the most essential element of self-defense.63 It presupposes actual, sudden and unexpected attack -- or an imminent danger thereof -- on the life or safety of a person.64 In the present case, however, according to the testimony of Marivic herself, there was a sufficient time interval between the unlawful aggression of Ben and her fatal attack upon him. She had already been able to withdraw from his violent behavior and escape to their children's bedroom. During that time, he apparently ceased his attack and went to bed. The reality or even the imminence of the danger he posed had ended altogether. He was no longer in a position that presented an actual threat on her life or safety. Had Ben still been awaiting Marivic when she came out of their children's bedroom -- and based on past violent incidents, there was a great probability that he would still have pursued her and inflicted graver harm -- then, the imminence of the real threat upon her life would not have ceased yet. Where the brutalized person is already suffering from BWS, further evidence of actual physical assault at the time of the killing is not required. Incidents of domestic battery usually have a predictable pattern. To require the battered person to await an obvious, deadly attack before she can defend her life "would amount to sentencing her to 'murder by installment.'"65 Still, impending danger (based on the conduct of the victim in previous battering episodes) prior to the defendant's use of deadly force must be shown. Threatening behavior or communication can satisfy the required imminence of danger.66 Considering such circumstances and the existence of BWS, self-defense may be appreciated. We reiterate the principle that aggression, if not continuous, does not warrant self-defense.67 In the absence of such aggression, there can be no self-defense -- complete or incomplete -- on the part of the victim.68 Thus, Marivic's killing of Ben was not completely justified under the circumstances. Mitigating Circumstances Present In any event, all is not lost for appellant. While she did not raise any other modifying circumstances that would alter her penalty, we deem it proper to evaluate and appreciate in her favor circumstances that mitigate her criminal liability. It is a hornbook doctrine that an appeal in a criminal case opens it wholly for review on any issue, including that which has not been raised by the parties.69 From several psychological tests she had administered to Marivic, Dra. Dayan, in her Psychological Evaluation Report dated November 29, 2000, opined as follows: "This is a classic case of a Battered Woman Syndrome. The repeated battering Marivic experienced with her husband constitutes a form of [cumulative] provocation which broke down her psychological resistance and natural self-control. It is very clear that she developed heightened sensitivity to sight of impending danger her husband posed continuously. Marivic truly experienced at the hands of her abuser husband a state of psychological paralysis which can only be ended by an act of violence on her part." 70 Dr. Pajarillo corroborates the findings of Dra. Dayan. He explained that the effect of "repetitious pain taking, repetitious battering, [and] repetitious maltreatment" as well as the severity and the prolonged administration of the battering is posttraumatic stress disorder.71 Expounding thereon, he said: