See this is the problem with using emotion and anecdotal evidence in a discussion like this and it's why I think you're wrong on so many levels and dangerously so.
Look what happened to your coworkers wife is awful and yes maybe in that very specific example having a gun prevented her getting raped. However we're not talking about one very specific isolated incident in one persons life. We're talking about an entire country here.
The simple fact is that having a gun personally makes you less safe. There is plenty of evidence to support this. That's the first major flaw with your argument. Feel free to do a bit of research on this if you want. Having a gun at home statistically makes you less safe and I'm pretty sure carrying a weapon only increases that risk. That's before we get into the increased amount of gun violence generally by allowing people to have weapons.
Secondly there are alternatives. You can always carry something like pepper spray and then you won't need to have every single person in society carrying a gun just in case.
Again though I ask do you think your chance of getting physically or sexually attacked is less in the US than other similar countries? In essentially all other developed countries people even in marginalised groups don't carry around weapons and they don't get attacked at a higher rate than in the US.
Mass murders are only one part of the problem. Look at how many people are killed by gun violence every year in the US. Removing more dangerous weapons will help but ultimately most of the violence is caused by handguns I'm pretty sure.
I don't get why you're arguing about this. He's already stated he'd be ok with moving semi-automatics with detachable magazines to Class 3 which would require a specific license that, frankly, most people would never get. That's pretty fucking close to outright banning them, it puts them in the same category as fully-automatic weapons and shit. It's a damn good starting point, basically leaving weapons with internal magazines and shit like breach action shotguns and bolt action rifles for the unlicensed masses, which he also said he supported licenses for those as well, though I'm sure they would be less strict than a Class 3 license.
I also don't think people are necessarily wrong when arguing against statistics because statistics are abstract. Everything is a trade off, banning guns would mean you save some more people but for a select few you're damning them to murder, rape, what have you. Because statistics are just that, the worst case doesn't happen to everybody, we wouldn't even call them statistics if that's how they worked they'd just be laws or facts or some shit, so clearly everyone who owns a gun isn't going to accidentally shoot themselves in the foot and then kill themselves with it while depressed or whatever. There's clearly a host of other factors that influence the overall statistics too, like if you're a single person with a gun you're a hell of a lot less likely to have a family member accidentally shoot another while playing with your gun since it'd just be you, if you're not depressed you're way less likely to use the gun to kill yourself, depending on where you live you may be less inclined(or more) to have your gun stolen and used in a crime elsewhere, they're excellent baselines for society but not as helpful for an individual.
I guess what I'm saying is this, ultimately I do agree than outright banning guns is the absolute best scenario for the most people I just get rubbed the wrong way when people who are the outliers of a statistic are basically told their experience is a lie and wrong, when it isn't, they're just the outlier.