All the teachers agreed on Monday that Sinead had to be one of the three, after her poor performance on Friday night.
Teacher Kevin said: "Sinead has put herself in this position and she has made the decision for us. There is no debate, the decision has been made."
Head Richard Park didn't mince his words either when he told the students who was on trial.
"This student didn't put in a great performance on Friday and they don't rehearse as much as they should do," he said.
Luckily Sinead took the news well. "I knew it, I knew it," she said, as her fellow contestants hugged her.