An employer can be held vicariously liable for the wrongful conduct of an employee, within the course and scope of his employment
By this you are saying that if the employee in question was an armed Security Guard that vicarious liability is a possibility since it is within the scope of employment. However; since the employee was not hired with an expectation to perform a function requiring offensive / defensive asset or personnel protection that this form of liability does not apply.
And you are right, I am not a lawyer...never said I was. My strengths lie in dealing with C.C.R. Titles 19 & 24.
P.S. Your three provided definitions do not make clear the Scope of Employment element.