First off, that's not an M9. Secondly, its not a real gun.
Hey everyone I'm sorry I wrote "stupid" on lots of gifs years ago. It's because I'm a sad and lonely asshole.
That is an airsoft toy. M9 slide can't come out sin city-style. Neither can 1911 slide so sin city got it wrong. The soldiers getting hurt were hurt by rear half of a faulty slide (bad metallurgy) - the slide snapped in two and at the time it was possible for rear half of the slide to fly backwards. This was fixed.
You my friend, are a moron. That is an airsoft gun.
That's a Beretta 92/M9. More than a few soldiers were hurt by similar failures.