The dagger was supposed to deliver a devastating blow, breaking a deadlocked Round Table vote and sealing the fate of one of two Faithfuls fighting for survival.
But instead it was millions of Celebrity Traitors fans who were left feeling 'stabbed in the back' when the BBC cut to the credits before King Kenny revealed which contestant he had banished with his game-changing power.
The 'pointless' cliffhanger has enraged viewers, who now face a six-day wait to discover whether Irish comedian Joanne McNally or Scottish actress Sharon Rooney has been banished from the castle.
Four contestants chose Ms Rooney, 38, and three backed Ms McNally, 43, leaving Kenny, 29, with the deciding double vote.
But as host Claudia Winkleman asked him to turn over his slate, the credits rolled.
One viewer who has watched both celebrity series told The Mail on Sunday: 'They are not creating suspense any more. They are just refusing to show us the ending.
'Friday's cliffhanger was especially pointless because there is only a twist if Kenny changes his vote. Otherwise, they have made millions wait six days to watch him make the same choice twice.
'I am still hooked, but by Thursday you are trying to remember why you cared. With only two episodes left, they should have finished the banishment.
Last night's cliffhanger has left viewers fuming as they must wait almost a week to discover whether Joanne McNally or Sharon Rooney (pictured) has been banished from the castle
Kenny has been left with the deciding double vote, but viewers say there is only a twist if he changes his vote (Ms McNally pictured in last night's episode)
'Last year the drama came from the contestants. This time it feels as though the editors are trying to wring two episodes out of every big moment.'
It is the second Friday in succession that the BBC has stopped the action at the crucial moment and forced its audience to wait almost a week for the payoff.
The previous Friday's episode ended during a murder in plain sight after Traitors Maya Jama and James Acaster attempted to make either Ross Kemp or Jerry Hall yawn in a room sprayed with 'sleeping powder'.
The programme cut away before either celebrity succumbed and six days later, viewers learned that Kemp, 62, had yawned first and been murdered.
And when the programme attempted to preserve another mystery this week, its own edit appeared to betray the answer.
Thursday's episode ended with Kenny beginning to write the next victim's name on a scroll after the Traitors narrowed their choice to Miranda Hart, Romesh Ranganathan and Sebastian 'Bash' Croft.
Fans noticed that his pen appeared to move upwards from the bottom of the page and concluded he was forming an 'M' for Miranda. A capital 'R' or 'B', they reasoned, would usually begin at the top. Their theory was confirmed within minutes of Friday's episode starting, when Ms Hart was revealed as the victim.
The viewer added: 'You cannot keep making viewers wait for an answer and then accidentally show it to them. It is still brilliant television, but it does not feel as sharp as last year.'
The verdict on social media was equally unforgiving, with viewers saying the 'cliffhanger trick' is beginning to wear thin.
One dismissed Friday's ending as 'pointless', while another said: 'God, I hate these cliffhangers. It feels borderline insulting to the viewers. Very cheap technique.'
A third accused the BBC of being 'sadistic' for making its audience wait almost a week for the result.
Despite the complaints, viewers are still watching in extraordinary numbers. Thursday's episode attracted an overnight audience of 10.03million on BBC1. EastEnders, the next most-watched programme, drew just 2.40million.
The final two episodes will air on Thursday and Friday at 8pm.
Even their castle has a secret... it's £2million in debt
The business behind the 19th century castle used in the series is said to owe millions of pounds to a mystery company
As the home of the Traitors, its shadowy rooms – and turrets – are used to a fair bit of intrigue. But Ardross Castle is harbouring a secret of its own.
Companies House documents reveal that the business behind the 19th century castle in the Scottish Highlands owes millions of pounds to a mystery company.
The latest accounts indicate the business, Ardross Castle Enterprises Ltd, owes creditors almost £2.6million, putting it £2million in the red.
The debt is largely due to an outstanding loan from Alness Ltd, which will not ask for its money back for at least a year 'or until the company has sufficient funds', according to the documents. It is not clear why the business required such a loan.
The castle and its 100-acre estate is 95 per cent owned by an offshore company based in the Turks and Caicos Islands in the Caribbean, Frontex Investments, while the remaining 5 per cent is owned by Donald McTaggart, whose family bought the castle in 1983.
But while the castle may be temporarily in financial difficulty, the Traitors effect may be paying off. In the 12 months to March 2025 – after three series of the hit show – the firm's debt shrank by almost half a million pounds.
Ardross Castle Enterprises Ltd was approached for comment.