[Susan Foreman]

Originally Posted by Rob4

...but the Doctor was never one to shirk from using violence as a means to resolving an issue, and in the past that usually involved a huge explosion or a UNIT gun battle. also companions could also be a bit handy with weaponry Leela/Ace/Captain Jack and who can forget the 4th Doctor's resort to chemical weaponry to deliberately kill off Dr. Solon?

But The Doctor was very much against them using weapons of any kind:

From part one of 'The Robots Of Death'

(Leela picks up the Tesh weapon.)
DOCTOR: You won't need that.
LEELA: How do you know?
DOCTOR: I never carry weapons. If people see you mean them no harm, they never hurt you. Nine times out of ten.
(Leela has her knife drawn as she leaves the Tardis.)

From episode one of 'The Greatest Shpw In The Galaxy'

(The Doctor is practising juggling with three cricket balls and the aid of a book called Juggling for the Complete Klutz.)
ACE [OC]: Professor?
(Some clothes get thrown through the interior door.)
DOCTOR: Yes?
ACE [OC]: Have you seen my Nitro Nine?
DOCTOR: Isn't it in your rucksack?
ACE [OC]: Yeah, but where's my rucksack?
DOCTOR: Interesting question.
(Ace emerges on her hands and knees with a long scarf around her neck.)
ACE: Things don't just vanish.
DOCTOR: No.
(One of the three balls up and doesn't come down again.)

And then there is this, from part four of 'Battlefield'

(Mordred lays Bambera's body on the ground by the Mobile Command post, then Ancelyn charges in. The two rivals fight, parting briefly as the Doctor walks between them and goes inside.
The countdown passes 60.)
MORGAINE: Too late, Merlin.
DOCTOR: Is it? Not while there's an abort button.
(Morgaine and the Doctor struggle.)
DOCTOR: If this missile explodes, millions will die, you will die.
MORGAINE: I shall die with honour.
(45, 44)
DOCTOR: All over the world, fools are poised ready to let death fly. A spark could turn into an inferno.
MORGAINE: What do I care? This is war.
DOCTOR: Is it? Death falling from the sky, blind, random, anywhere, anytime. No one is safe, no one is innocent? Machines of death, Morgaine, are screaming from above, of light brighter than the sun. Not a war between armies nor a war between nations, but just death, death gone mad. The child looks up in the sky, his eyes turn to cinders. No more tears, only ashes. Is this honour? Is this war? Are these the weapons you would use? Tell me!
MORGAINE: No.
DOCTOR: Then put a stop to it, Morgaine. End the madness.
(4, 3, 2. Morgaine presses the red abort button at 1.)

And this classic scene from part two of 'The Happiness Patrol'

DOCTOR: Hello.
DAVID: Get back or I'll use the gun.
DOCTOR: Yes, I imagine you will. You like guns, don't you.
DAVID: This is a specialised weapon. It's designed for roof duty, designed for long range. I've never used one up close before.
ALEX: Let him go.
DAVID: No.
DOCTOR: No. In fact, let him come a little closer.
DAVID: Stay where you are.
DOCTOR: Why? Scared? Why should you be scared? You're the one with the gun.
DAVID: That's right.
DOCTOR: You like guns, don't you.
ALEX: He'll kill you.
DOCTOR: Of course he will. That's what guns are for. Pull the trigger, end a life. Simple, isn't it.
DAVID: Yes.
DOCTOR: Makes sense, doesn't it.
DAVID: Yes.
DOCTOR: A life killing life.
ALEX: Who are you?
DOCTOR: Shut up. Why don't you do it then? Look me in the eye, pull the trigger, end my life. Why not?
DAVID: I can't.
DOCTOR: Why not?
DAVID: I don't know.
DOCTOR: No, you don't, do you.
(The Doctor takes the gun from David.)
DOCTOR: Throw away your gun.
(Alex drops his gun.)