Jac Naylor has been struggling with her declining mental health and, after months of suffering in silence, it all became too much for her in last night's Holby City.
On Tuesday (December 3), her anxiety only worsened when she had the task of performing life-changing surgery on her mentor and friend Elliot Hope.
In worrying scenes, viewers saw Jac's usually super-tidy office covered in papers about the surgery she was about to perform on Elliot.
With mess strewn across every surface, Jac could be seen practising the operation.
I was sobbing at the end - poor Jac falling apart.... Heartbreaking.
After last week's emotional outburst in theatre, it's understandable that Max was concerned and booked her in for an appointment with Occupational Health.
Already feeling stressed and unsupported by her colleagues, Jac pinned all her hopes on seeing her daughter Emma.
She had arranged for ex-husband Jonny to bring Emma to Holby so they could enjoy an early Christmas together... But when Elliot's condition suddenly became critical, Jac had to take him into theatre in a very fragile mental state.
Viewers know that Elliot is a very important person to Jac, and he returned to Holby at a very critical time for her as her mental struggles worsened.
Clearly torn between her promise to operate on Elliot and feeling guilt over her daughter Emma, Jac's mental state was further compromised when she received a call from Jonny while operating on Elliot.
The episode ended with Jac rushing out of the surgery room to get Emma, leaving Elliot in a life or death situation.
She eventually lost control and let her emotions out in scenes viewers found "painful to watch".
Many of those watching from home praised actress Rosie Marcel's performance during the emotional scenes.
One wrote: "Amazing acting from Rosie, sad seeing Jac breaking down when we have always known her to be so strong."
Another said: "Rosie Marcel was amazing tonight in Holby... What a great actress to pull that performance off and on such an important topic... We love you Jac."
A third added: "The acting of Rosie Marcel as Jac Naylor in Holby City was phenomenal. Mental health really is important and should not be taken lightly."
"So very sad," said another. "Rosie is a brilliant actress and so is Alex well done to both of them. Jac really needs Fletcher now more than ever. Holby please get them together."
"I was sobbing at the end - poor Jac falling apart.... Heartbreaking," said one more.
Actress Rosie Marcel has now revealed the aftermath of the devastating breakdown in an interview with Digital Spy, saying: "She's going to struggle more.
"I think she's at a really critical point in her life. I don't think she's been dealing with the stresses that have been occurring recently."
The actress went on to discuss how other events from Jac's past have led to her crumbling, and explained: "I don't think she ever dealt with her sister dying, being shot, nearly being paralysed."
Rosie said that Jac's condition will get "significantly worse" before it gets better.
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