Sam (played by Charlotte Salt) rushed to the scene of the accident along with her colleagues and ex-husband Dylan Keogh (William Beck).
She could be seen helping fellow paramedic Iain Dean (Michael Stevenson) help two young women out of their car which had gone into the side of a petrol container.
The pair managed to get the women to safety just as the tank blew up and Sam was seen being thrown against the side of the ambulance.
She appeared to be okay throughout the remainder of the episode, however, in the final few moments it was revealed she had shrapnel lodged in her side.
It seemed Iain had appeared at the ambulance station where Sam had been on her own just in time.
However, as he tried to treat his colleague’s wound, she declared it was too late and she died in the back of an ambulance.
Iain was visibly distraught over Sam’s death and could be seen clinging to her lifeless body and banging his fist against the side of the vehicle.
Viewers were also distraught and took to Twitter to comment on her death, with one viewer writing on Twitter: “Why did she have to die #Casualty #sam.”
Another added: “Naaah, Jeff, Cal and now Sam you can’t do this to me #Casualty.”
It seems as though her death will affect Iain greatly in upcoming episodes if a preview for the rest of the new series is anything to go by.
Following the end of the episode, Casualty shared a trailer on their official Twitter account hinting at more tragedy to come.
At the end of the trailer, Iain could be seen mourning Sam as he stood next to her dead body in the morgue.
As he looked at her lifeless body, he apologised for not saving her: “I’m so sorry Sam. This is all my fault.”
Could Iain be overcome with grief in upcoming episodes and make the decision to take a break from his job?
But it seems as though Iain won’t be the only member of the team to be struggling.
The teaser clip appeared to show Alicia Munroe (Chelsea Halfpenny) will seek justice after she was sexually assaulted by Eddie McAllister (Joe Gaminara).
In the trailer it looked as though she was in court, perhaps waiting to find out if Eddie would be prosecuted for his actions.
Eddie was also featured and appeared to be confident that he would get away with his crimes.
Casualty continues Saturday on BBC One.