Note that http://www.guardian.co.uk/news/datablog/2011/jan/10/gun-crime-us-state states that NY only had 445 murders by firearms in 2011, which again for 20 million people makes this fairly comparable to the rates in France wich has much stricter gun control.

I was a bit curious about that number of 750 murders with firearms per year in NY (I assume state, not just NYC), so I tried to find statistics in France, where I live.

I only found statistics for 1999 so it's pretty old, but we had 2600 deaths by firearms in the whole (roughly) 60 million-people country, including 2000 suicides (does that count as murder in your number?) and 100 accidents (not sure if that means self-accident or killing someone else).

Anyways, 600 people died of firearms outside of suicides for 60 million people that year. Sounds way too many for me, but then compared to 750 for NY (which Wikipedia says about 20 million people) it's still about three times less.

I read some chemistry teacher stories in this thread, and most do not show the teacher from a bad angle.
Mine decided to demonstrate that sodium reaction in a glass aquarium filled with water. After one guy recalled from the year before that there would be a reaction, we decided to get some distance from the teacher as he grabbed a piece that seemed just "too big" to not do anything stupid.
He told us to approach to see better, and we got away and prepared to duck for cover.
He then decided it was maybe unsafe and put a glass cover on top of the aquarium.
And that's when the aquarium exploded shattering glass across the whole classroom and doing quite some damage to him.
But then again, it's the same teacher who told us one morning he blew up his garage door with his car because he forgot to open it.
He also told us one liquid was very dangerous for the eyes only after one smart kid threw it with a pipette in the face of a girl who ended up evacuated at the hospital.