I would imagine she would need to be screaming for help and you had to feel the immediate need to protect her. If someone is screaming for help I seriously doubt anyone would object.PC §9.33. DEFENSE OF THIRD PERSON. A person is justified in
using force or deadly force against another to protect a third person if:
(1) under the circumstances as the actor reasonably believes
them to be, the actor would be justified under Section 9.31 or 9.32 in
using force or deadly force to protect himself against the unlawful force
or unlawful deadly force he reasonably believes to be threatening the
third person he seeks to protect; and
(2) the actor reasonably believes that his intervention is immediately necessary to protect the third person.
Now as for pulling your gun, the use of deadly force must be justified before showing it. I'm not real sure if this would fall into protecting a 3rd person's property.