Martin, who is a bridal boutique owner, revealed the news after this week's task, during which the contestants had to sell bao buns to the public and pitch a bespoke bun to corporate client.
Following her exit, Shannon revealed the reason she quit the show as she admitted she'd had "doubts" prior to signing up.
"I think that going into the process, I was already having some doubts of whether I should go in or not," she explained. "But when you’re given such an amazing opportunity, you’re not ever going to turn that down, it’s an opportunity of a lifetime that I’m forever grateful for."
Shannon says she struggled to focus on the tasks at hand as she was worrying about her own business back home in West Yorkshire.
She continued: "During the bao bun task, I was there in the kitchen thinking, ‘Why am I here? What am I doing here making bao buns in a kitchen when I can’t cook as it is?’ I just really felt like I couldn’t focus on the tasks because I was constantly thinking about what was going on at home. What’s happening with the business? Is everything OK?
"I knew in the back of my mind that of course everything would be OK, the team are amazing. But I’m a perfectionist, I need to know what’s going on all the time and not being able to know how things were going on at home or what was happening at work was really hard for me. The unknown is definitely not something I’m good at."
Shannon finally decided to leave the show, adding: "The more I thought about it, the more I thought, ‘Am I in here for the right reasons? Do I really want a business partner? Is this what I want? Do I want my life to change?’ and it really made me realise I love my life, I love the team and I love everything about my life."
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While Shannon believes that she has what it take to win the show, she says: "I wasn't in it for the right reasons" and "there were more deserving people there than me and it was not right for me to stay in the process".
The bridal boutique owner quit the show before finding out that the girls had actually won this week's task and made more profit than the boys. Had she have stayed, Martin would have progressed to the following week.
This meant that Lord Sugar still had some firing to do, with one of the boys at risk of going home. It was later decided that Kevin D'Arcy from Dublin would be leaving,
“Kevin, you sold the bao buns too low. You were more focused on revenue rather than profit and so it is with regret, you’re fired," Lord Sugar explained as he gave Kevin the firing finger.