Casualty viewers were stunned tonight when a major character died within seconds without warning.
Mason Reede, played by Victor Oshin, was found lying lifeless on the floor of a store room at the very start of the episode.
The junior doctor was discovered by Rash, who desperately tried to revive his colleague to no avail.
His body was cold and it was evident he had been dead for some time ads rigour mortis had set in.
Some Casualty fans were convinced they had missed an episode after watching the shock death.
Taking to Twitter , one stunned Casualty viewer asked: "How is Mason dead? did not see that coming, have I missed an episode?"
"Wtf is happening today I blink and boom dead Mason," added another.
A third said: "Wth? Mason????? Did not see that coming."
"OMG - didn't expect that in #Casualty I was only just starting to warm to Mason a bit," said a fourth.
None of the staff could remember when they last saw Mason and didn't even know he was supposed to be in work.
Speaking to the police, Rash said: "If he was having a hard time, we didn't know it. We couldn't have known."
This led some viewers to speculate it was suicide, but all will become clear in next week's episode.
In a spoiler for next week's episode, Dylan explains that Mason died of a pre-existing heart condition.
He tells the staff: "Those higher up no doubt breathing a sigh of relief, despite the fact this ED is an accident waiting to happen."
There are also tensions when Connie finally returns and claims she is resuming her position as clinical lead.
*Casualty airs Saturdays on BBC One at 9.20pm
