White tigers maul man to death in Singapore zoo

Morin Bin Monkton, 32, a Malaysian working as a cleaner at the zoo, died after being attacked by three white tigers at the Singapore Zoo on Thursday. He was a contract worker in Singapore zoo, according to the local news :

"He was throwing things around and as he was walking out of the zoo, he passed comments like 'Goodbye, you won't see me again'. He later jumped off the ledge into the water,  waving a broom and pail to white tiger, once he was inside the enclave, The largest tiger lunged at him and he fell and quickly recoiled in a foetal position while trying to cover her head with the pail. Visitors thought it was a show until one of the tigers bit his back and started dragging him to the tigers' den. One zoo keeper who was nearby quickly used his walkie-talkie to raise an alarm. Other 20 zoo keepers came forward and managed to get the tigers back in the den. The police was called and an ambulance arrived, He died shortly after."

images from straitstimes.com

I am very curious why the man jumped off  ledge into the water, walk towards to the tigers area, and finally killed by animals. What kind of problems he had, however life is not that bad although everyone of us have different "headache".