The BBC hospital drama had already teased that one character would be dying, but some fans didn’t see it coming.
While Sam Nicholls (played by Charlotte Salt) appeared to be keeping it together as she played her part in the rescue mission, things weren’t as they seemed.
Alone at the ambulance station, Sam was suddenly gripped with horrendous pain and could be seen clutching her side.
As she pulled up her top, the paramedic exposed a gruesome wound as it was revealed she had shrapnel lodged in her liver.
Sam crawled into an ambulance as she was unable to move any further but was soon found by Iain Dean (Michael Stevenson).
“Sam what’s happened?” he asked before identifying her injury and radioed for backup: “Penetrated abdomen wound.”
He tried to comfort Sam as he said: “Come on, stay nice and still, keep breathing. Let me get some fluids yeah?”
But poor Iain couldn’t find any on the ambulance, and Sam urged him not to leave her side.
“Iain, please don’t leave me, please don’t go I’m scared,” she cried out.
“Don’t be scared,” he said as Sam told him her time was up.
“Iain, it’s too late,” Sam declared as she struggled through her immense pain.
“It’s not too, late, what are you talking about? Keep looking at me, keep talking,” a frantic Iain exclaimed.
Iain desperately tried to resuscitate his colleague but it looked as though it would be too late.
The audio was muted as Iain clutched to the lifeless body of his friend and colleague.
Devastated fans took to Twitter to express their sadness at Sam’s harrowing fate.
“Naaah, Jeff, Cal and now Sam you can’t do this to me #Casualty,” one fan tweeted.
Another lamented: “Why did she have to die #Casualty #sam.”
“#Casualty3006 No No No they did not just kill off Sam in #Casualty….@charlottesalt you will be sorely missed…best actress and character ever xx,” a third added.
Casualty continues Saturday on BBC One.