Unforeseeable consequences deals with additional outcomes to an injury that could occur, without the realization or knowledge by a person found negligent damages
The main reason behind a defendant being held liable for negligence, and damages, is when the act was clearly 'foreseeable' and caused directly by the probable and natural consequences of an act that was done by the defendant, or an act that the defendant failed to take part in.
This does not include any outside contributing factors, including actions by the plaintiff themselves. Unforeseeable consequences are harder to prove and demonstrate, and make for tedious research. Sometimes points like these are the main contributing factors to controversy in tort law, and more specifically in negligence cases, which adds to the reputation of such cases.