It isn't about guns per se, it's about all lethal items. The how of suicide is just as important as the why. Having anything in your home that is a highly efficient means of killing yourself greatly increases the risk that you will in fact kill yourself. Most suicidal intent is temporary and most suicidal behaviour is impulsive, so restricting access to highly effective means of suicide is a vital tool in preventing suicide.

In 1998, the UK restricted sales of paracetamol (acetaminophen) to packs of no more than 32 tablets. The result was a lasting reduction in suicides by paracetamol poisoning, with no commensurate increase in suicide attempts by other means. Several studies have found that interventions like installing suicide prevention barriers on bridges can reduce the suicide rate rather than merely changing the choice of means.

https://www.bmj.com/content/346/bmj.f403

https://www.hsph.harvard.edu/means-matter/useful-links/bibli...

If you take an overdose of tablets or slit your wrists, you'll probably survive with suitable medical care. You probably have the opportunity to change your mind, call an ambulance and save your own life. Very few people survive a gunshot wound to the head; all of them sustain life-altering injuries.

You have the right to own a gun, but that comes with responsibilities. You need to recognise that your gun poses a serious risk to you and your family, especially if it isn't consistently stored in a suitable gun safe or someone in the house is at risk of suicide.

If you're worried about the mental health of a family member, controlling their access to convenient and highly lethal means of suicide could well prevent an impulsive decision from becoming a tragedy. Clear out your liquor cabinet, throw out any surplus medication and get your gun out of the house.

http://www.meansmatter.org/

Rather than offer your thoughts on what may have happened, you might be interested in reading about actual research into suicide. The gist is that many suicides are impulsive when an easy method is available– most often a gun.

https://www.vox.com/2015/7/30/9068255/suicide-impulsive-gun-...

And I'm saying there were other methods just as easily available if not more so if she was already in the bathroom.