2 (a) That's probably wrong. The courts have been reluctant to apply volenti non fit injuria in rescue situations where it can be argued that rescuers are not really 'free' to avoid the risk.
In this case Greer CJ said that volenti non fit injuria did not apply to a person who has "under an exigency caused by the defendant's wrongful misconduct, consciously and deliberately faced a risk, even of death, to rescue another from imminent danger of personal injury or death, whether the person endangered is one to whom he owes a duty of protection, as a member of his family, or is a mere stranger..."