[T]here may be a legal obligation to take positive or affirmative steps to effect the rescue of a person who is helpless or in a situation of peril, when the one proceeded against is a master or invitor, or when the injury resulted from use of an instrumentality under the control of the defendant. Such an obligation may exist although the accident or original injury was cause by the negligence of the plaintiff or through that of a third person and without any fault on the part of the defendant.