Plenty of them, almost all mass killings end with the perpetrator being shot by police or committing suicide.
Your continued use of the term machine gun exposes you as a clueless idiot. Cruz had an AR-15 which is a rifle. Shooting unarmed kids with a rifle from short range isn’t difficult. Coming up against a cop armed with a Glock 22, who takes you by surprise, is a different proposition.
You are defending cowards here, which of course means you are a coward yourself, as like attracts like.