Condition #7:
The final condition necessary to permit speaking what would otherwise be rechilus for a constructive purpose is that conveying the information does not cause undue harm to the subject. Constructive intent does not justify causing harm to another person.
Therefore, one cannot inform a person that someone else is about to harm him if the person will respond by harming the plotter. This applies not only to physical or financial retaliation, but even to retaliation in the form of loshon hora in a manner prohibited by halachah.
