The man told police he was shocked that his intimate moments were streamed to a national audience.
He is believed to have self-skidded, the police said.
Victims would be asked to transfer funds urgently to assist in the Straits of Hormuz situation.
The 71-year-old suffered head injuries, multiple broken ribs, severe abrasions on his arm and a lumbar spine injury.
Photos showed the man lying in a pool of blood at the foot of the block.
35 others have been injured, said Bangkok's police chief.
The store said it had to close for the day due to the "overwhelming crowd".
Some dubbed it "MRT Gala", a word play on the annual Met Gala.
Remember to bring your umbrellas.
A flash flood warning was issued at least 40 minutes before.