For former Penn State exchange student Oliver Ferrari, an elderly couple clinging to each other for safety will forever be a reminder of Thursday morning's subway bombings in London.

Ferrari, a 20-year-old student from the University of Wales, Aberystwtyh, was on a westbound subway car going to work Thursday, when suddenly, he said, he heard a loud "bang" that caused the car's windows to shake as a bright light illuminated the Underground station.

The subway was approaching Edgware Road about 9 a.m. GMT (4 a.m. EST), passing an eastbound train -- one of the three Underground trains that exploded.

"The entire carriage was filled with thick, black smoke," Ferrari said. "At first, I don't think anybody realized it was a bomb."

Ferrari said he heard screaming farther down the Underground and saw a man lying outside the car with his arm stuck between the doors. The brick wall dividing the two subways was demolished, he added, and debris had sprayed everywhere.

"Someone was yelling that a man had been killed when he was thrown through the brick wall during the explosion," Ferrari said. "Through all the rubble, it was so hard to determine between the two trains."

Passengers on his Underground calmly tried to help those who were shocked and bleeding from the cuts on their hands and faces, Ferrari said. About 30 minutes later, the electricity was cut, and train operators helped six or seven wounded passengers out of the car before releasing the remaining passengers.

It was then that Ferrari saw the elderly couple.

"I could see the fear and uncertainty in the way they were holding each other," Ferrari said.

Ferrari tried to continue his daily routine, not completely sure of what happened.

"I called my father and he told me it was a bomb," he said.

Ferrari then went to work, but was so shocked by his experience that he was sent home.

Thursday night, Ferrari went to a bar and noticed people were quiet and thoughtful about the day's events. He could only describe the experience as "a bad day, quite shocking, very bloody."

Ferrari spent the 2004-05 academic year at Penn State, and five of the friends he made during that time visited him in London earlier this summer.

Nelson Navarro (sophomore-crime, law and justice), who met Ferrari while the two lived in Pinchot Hall, said when he heard of the attacks, he immediately began worrying about Ferrari. Navarro contacted him online to make sure he was OK.

"Luckily, we talked and Ollie said he was fine, but he saw a lot of people who were not OK," Navarro said.

All Penn State students currently studying in London or surrounding areas have been accounted for, said David Larsen, director of the Arcadia University Center for Education, which coordinates Penn State students in London.

Larsen was notified of the attacks at 5 a.m. EST. The program's London staff immediately told him that all students were accounted for.

John Keller, director of the Office of Education Abroad, said Penn State currently has one student studying at an internship program in London through Arcadia University and 12 students studying outside London in Sussex, England.

Keller would not release any of their names.

Ferrari said even though he is still shaken, the attacks would not stop him from living his life.

"I know I have to get up and go to work tomorrow, and I'm going to take the train to get there," he said.