The 28-year-old, who had been performing musical theatre on the Celebrity Eclipse since July, was one of just 300 people left on the 2852-passenger vessel before boardingthe Celebrity Reflection in Barbados.
"This round should end on June 19. I now get to take daily walks as I don't have access to fresh air inside this cabin," she said.
"I have got my hopes up so many times over and over about coming home, that I have just let it go at this point.
Marshall added: "I did consider booking my own flights home when I arrived in Heathrow, and just making a run for it."
The performer said that while she is geographically the furthest away from Hawke's Bay as you can get, it felt comforting to be somewhere that offers more options to fly home commercially.
"I'm not entirely sure why I am having to wait so long here, as I am aware there are quite a few flights to Auckland from Heathrow," she said.
"I think it's something to do with being a crew member and the company not being allowed to book me flights on certain routes and having to quarantine on the way."
Marshall said while her nightmare journey may not yet be over, she is proud of how New Zealand has handled the global pandemic.
"I am so incredibly happy and proud of New Zealand," she said. "It really does make me look forward to going home more, knowing life can basically go back to normal when I return.
"But it is such a bittersweet feeling having to wait and watch, but if I can be back and out of quarantine by mid-July, I can handle waiting a bit longer."