Got it.
First scenario: Same answer as Jeff. If he hasn't seen me, doesn't know of my presence and I have surprise, he's going to sleep by the time he feels the sleeper. I want to control his head and breathing. Controlling the head allows me to keep his body from harming me as I control where it is moving [ control the head and the body follows ]. Controlling his briething will get his attention immediately away from the SO, I want that and I want that right now.
If he has seen me but I'm able to reach him as he does and turns to me, I have accomplished the primary [ getting him off the SO ] by my mere presence. Then he has to deal with me. If he turns with a knife threatening, if I'm close I'm going for it, I don't suggest or recommend this to be followed by anyone else.
My training unarmed will prevent him from likely getting a core shot into me and I'm going to go for his hand to control knowing I'm likely going to get cut. No time perhaps to even think about pulling the knife.
If I am just entering the home and hear a struggle I'm drawing the blade as I get through the door. I'm going to be ready to deal with possible multiples immediately that may be armed with guns, knives, bats, whatever and are a threat until proven otherwise.
If it were available before getting to the attack in the house, I'm going to grab one of the guns stashed about the house and ready to go. It's all going to be fluid, with forethought, the way my house is set up, If the probelm is upstairs in the bedroom in your scenario, I'm going to be able to get to two guns before hitting the stairwell where the swat tactics will kick in relative fatal funnels, stairwell tactics, though very dangerous under any circumstances, and go for it gun in each hand.
If I can't get to the guns, it's happening in the next room, knife may be drawn and ready for multiples. My SO's struggles and the amount of urgency I hear, all the sensories will be fast paced while on the move.
I've been attacked unarmed from behind, while doing his buddy H2H. Had a gov45acp crossdraw and two knives on me. Never pulled any of it, or thought of them, and proceeded to give the guy that hit me from behind a new face. Later, the next day, I had my jaw wired for 6 weeks.
I mention it as it is possible one will forget they have weapons about them when in the heat of the moment, especially startled, hit from behind. That guy sent me back a good ten feet, I saw the stars, the blackness, almost out but not quite. Never went down, kept enough balance to stay up staggered. Right back in the fray with no thought to weapons.
Can't say for sure, considering past experiences where time is of the essence and danger close that I wouldn't just rush into the equation without thinking about weapons until I was forced to think about it by an outside stimulus. Could also be too late to get to it once the thought is there.
There are a lot of variables, distance, time, urgency, stealth to the problem or not, it will be fluid, and hard to guess where it will lead, but it's important to remember you may not even think to access it immediately when the SO is right there being harmed. I want my body on his body and him to now concentrate on me, not her.
If I stab him from behind [ he hasn't seen me ] and I run in and stab him in the neck, to get him off of her, and he has a knife to her throat or near her at all when I do that, she stands a good chance of taking one of his shots, maybe several while you are giving him his. His attention may be to move to you and cut her while moving to address you. I am not enamored with the idea of damaging him but having to wait a split second for him to react.
If he has turned to face you[ knows you are present before you can take him ], he may hold her a hostage threatening her for you to give stop your advancing, knife or no.
Then you are into more than the question actually asked so I'll stop there.
Second scenario: If I know I'm under attack [ and alone ] by a pipe, one person, I will likely stay unarmed for the moment. I've had people come at me with pipes and a few bats at times. Never pulled the gun or knife on me at the time when it was one on one. Never thought about them. Didn't have time.
Good thing too. If I had gone for the gun or knife I would have been clocked doing so and taken major damage. If it's up close and personal as it starts, relying on a weapon like a knife against a club or pipe gives him an advantage to my thinking. You pull the smaller weapon, he has a weapon that outdistances yours in reach, you are a threat now but he still has the avantage. Though the knife hand can be used to parry, I want both available to me immediately to grab, move, and parry.
I'm not prone to trying to fill my hand with a weapon I guess when it's here and now. Given some minimal time [ say a few seconds ] and distance I'll run, if alone in your scenario. No gun on me? I'll run if given the chance. I'm not that fast but he's gonna have to catch me. If I'm leaving the local store, there will be cars to get between you, people about or at least inside at the register who may see whats going on while you play cat and mouse around the cars. You don't have to run far or for long to get objects between you.
None of the above is a suggestion for anyone else to attempt anything mentioned or described in this thead. Others options will vary depending on many factors and each needs to understand and decide their own course of action based on those factors, hopefully with forethought and not hindsight.
Brownie