He apologized for his "misplaced outrage."
During a town hall-style forum that was being taped for ABC on Saturday, Fuller became angry after Trent Humphries, the leader of the Tucson tea party, suggested that discussions about gun control should wait until after the victims' funerals. Fuller then stood up, took a picture of Humphries and yelled, "You're dead!"
Police arrested Fuller for disorderly conduct and had him involuntarily committed to undergo a mental health evaluation. He is still in the hospital.
"He sounded very, very remorseful for one thing," his girlfriend, Dorothy Deruyter, told the AP. "He wasn't his buoyant personality but he wasn't angry either, and he realizes it was an inappropriate statement."
She said that Fuller, who has no children or family, has been dealing with the tragedy on his own. On Jan. 8, he was shot in the knee and back at Rep. Gabrielle Giffords' "Congress on Your Corner" event.