Should schools have metal detectors

Sorry if this was already posted or if there are too many similar topics I’ll remove it.

Today there was almost a school shooting and the high school my brother and many of my friends younger siblings go to. The kid ended up pulling a gun out and the school officer shot him so the situation de-escalated and the rest of the students are safe. A lot of people on Facebook were posting that the school should have metal detectors like other schools in that area.

This is also the same school the girls involved in the slender man stabbing (if you know about that case) went to.

**extra question what are more ways we can prevent this from happening? We have more anti- bullying campaigns and mental health awareness than before.

Edit: I should have clarified my 2nd question- it wasn’t directed towards shootings but more so towards how to stop people from wanting to do things like that and how you would put that plan into action.