The "unlucky bastard" was an unnamed San Diego resident, living in the city in 1997. When a lone male Tyrannosaurus rex went on a rampage through the city, he became one of the many citizens caught up in the ensuing chaos, eventually being killed and eaten by the creature.
The San Diego incident
When a captured T. rex Buck breached containment aboard the S.S. Venture and went on a rampage through the streets of San Diego, the unnamed citizen was forced to flee with the rest of the crowd from the enraged animal. As the man and the other civilians ran around a corner in terror, the man subsequently found his path blocked by a parked car. At that moment, the T. rex snapped at several businessmen running alongside him, leading to him being trapped between the parked car and the dinosaur's head.
With his path blocked, the man quickly noticed his only avenue of escape: a video store. Thinking quickly, he ran for the store to take shelter — unfortunately, this led to the Tyrannosaur immediately noticing him "splitting away from the rest of the herd". With the massive carnivore closing in, the man managed to open the door. Unluckily, at that very moment the creature snatched him in its jaws and lifted him off the ground.
Screaming in agony, the hapless resident was crushed in the animal's powerful jaws until he could do nothing more than meekly choke. The Buck subsequently set his barely alive body behind a parked car and stepped on him, killing him before feasting on his mangled corpse.