So it could have been much worse;
Quote
Officials alleged that Chou secured church doors with chains and tried to disable locks with Super Glue. He also attempted to nail at least one door shut, Barnes said. Bags containing magazines of ammunition, as well as four Molotov-cocktail-like incendiary devices, were found at the scene.
On Sunday, churchgoers had just finished an after-service lunch — a special bento with teriyaki chicken — in honor of a beloved longtime pastor who had just returned from two years in Taiwan when gunfire erupted.
“Dr. Cheng is a hero in this incident, based on statements from the witnesses and corroborated by other means. It is known that Dr. Cheng charged the individual — the suspect — [and] attempted to disarm him, which allowed other parishioners to then intercede,” Barnes said.
After Cheng was shot, the visiting pastor, Billy Chang, struck the suspect with a chair when his weapon jammed, according to police and witnesses.
It sounds like he was preparing for the vastly more dangerous "lock everyone in the building and burn it down" strategy, but instead tried to rambo it and got taken down when his gun jammed.