The schoolgirl was knocked on her head and said she knew the situation was serious when she heard Mr Fyfe moaning and saw blood on his face.
"I dialled 111 and held a T-shirt to his head because there was so much blood," she said, adding that the girls all knew the driver.
While most of the students on board were "freaking out", Samantha made her way to the front of the bus, taking over the conversation with the emergency services operator, allowing Caitlyn to check the driver.
"I asked him if he was breathing. He was struggling. Caitlyn felt for a pulse and asked him where it hurt. The operator told us to keep pressure on the wound on his head," Samantha said. "I was trying to keep calm, for him."
Puke made sure the doors were open to let everyone off the bus, then she flagged down another bus driver, who could tell there was something wrong.
Another bus driver arrived and took over, with emergency services arriving shortly afterwards. Mr Fyfe, in his 70s, was later flown by helicopter to Auckland Hospital, where he was due to undergo surgery yesterday.
The girls all wanted to visit the driver in hospital and thank him for getting the bus off the road safely.
"I want to tell him, 'Don't worry about us, we're fine'," Samantha said.
The girls said the incident made them nervous about taking a bus again.
"I cried all night long, and didn't want to take a bus this morning," Caitlyn said.
Whangarei Girls' High School deputy principal Kevin Dean said he was proud of the girls.
"They acted superbly. I'm proud of the responsibility and initiative they showed in the situation, as well as their compassion," he said.
Mr Fyfe was praised by NZBus operations chief executive Shane McMahon for ensuring the students' safety.
When he visited the driver in Auckland Hospital on Tuesday Mr Fyfe's main concern was whether the kids were all okay, Mr McMahon said.
The driver had passed on his thanks to the students who cared for him while they waited for an ambulance to arrive.