Most epic entry

Which Shooter did the most epic thing to start the rampage?

Steven Kazmierczak kicked a door open with extreme force, James Holmes threw tear gas, George Hennard crashed his truck into Luby's.

Definitely Abdul Emir Khalaf Sabhan.

at around 11 a.m., said neighbour's grandchildren heard shots from Sabhan's house. When the woman went to investigate she saw a man running agitatedly from the building, shouting: "They are all finished!", but when she knocked on the door Sabhan opened, cigarette in mouth, and told her that everything was fine and she should go back home. Later that day 11 people were killed.

Source:Amok wiki

Not really epic per say, but James Huberty's entry of walking into the McDonald's, aimimng the shotgun at an employee, and having the gun jam on him, making everyone think he was just a prankster, is quite a unique way to cap things off.

Devin Kelley shouted "everybody die, motherfuckers" before committing his shooting in the Church.

Nanterre mayoress announced that the meeting was over, and Richard Durn stood up and replied: "No, it is just starting" before shooting at the town hall.

Unconfirmed but apparently Walter Seifert proclaimed that he was "Adolf Hitler the second" just as he began his attack.