Only two days remain until AEW's next major pay-per-view, Forbidden Door. The event is in collaboration with New Japan Pro-Wrestling and will be held in London at The O2 Arena. Interestingly, this will be the first time that the Jacksonville-based promotion hosts Forbidden Door outside of North America.The PPV, meanwhile, is marked with some high-stakes title clashes, including the AEW World Championship, the Women's World Championship, the Tag Team Championship, and the TBS Title, among others. In pro wrestling, title changes are a key milestone in progressing ongoing storylines, and AEW is no different. However, because of the importance of the right title change, it must be done with careful consideration, and Tony Khan must be wary, as it significantly impacts the future direction of his promotion.With that in mind, let's look at three AEW stars who must not become champions at Forbidden Door.#3. MJF must not win the AEW World TitleMJF's time in the Jacksonville-based promotion has been eventful of late, to say the least. The Salt of the Earth experienced highs and lows during this time. He won the Men's Casino Gauntlet Match at All In but got kicked out of The Hurt Syndicate. Friedman then got coaxed into using the contract for a title opportunity at Forbidden Door, but then got it reversed at Dynamite this week while still keeping the title shot, which means even if he loses, he's guaranteed another title shot in the future.There is no doubt that the Wolf of Wrestling is well-equipped to be the AEW World Champion. However, it's still too soon for him to take over from Hangman Page, who is in the process of solidifying himself as the top babyface in the promotion. Tony Khan must ensure that Hangman Page defeats MJF at Forbidden Door and continues to hold his promotion's top prize.#2. Nigel McGuinness should not win the IWGP World TitleAt Forbidden Door, NJPW's Zack Sabre. Jr will defend his IWGP World Heavyweight Championship against AEW's Nigel McGuinness. The 49-year-old veteran had earned this opportunity by winning a four-way match at Collision last week. Fans can expect a technical masterclass when Sabre Jr. and McGuinness take center stage at the O2 Arena in London.Many will predict Sabre Jr. to defend his title successfully, and in this case, Tony Khan must make sure that he sticks to that result. McGuinness is operating at the tail end of his in-ring career and will retire sooner rather than later. Putting a title on someone who has actively transitioned into other roles within the industry would be counterproductive for the promotion.#1. Athena shouldn't win the Women's World TitleUnlike MJF, Athena chose to cash in her Women's Casino Gauntlet contract for a shot at the AEW Women's World Championship well before Forbidden Door. Since her decision, The Fallen Goddess has been a menace to deal with for champion Toni Storm. The reigning ROH Women's World Champion has been actively attempting to undermine The Timeless One during the buildup to their bout at the PPV.While the match has garnered enough interest from fans and is expected to be a blockbuster, the Jacksonville-based promotion must make sure that Athena does not dethrone Toni Storm at Forbidden Door. Much like MJF, Athena is a great candidate to hold the Women's Title. However, The Fallen Goddess already has the most coveted women's title in ROH, and winning its AEW counterpart would make things complicated. Moreover, Toni Storm gained a lot of momentum after successfully defending her title at All In: Texas, and Tony Khan will be better off building on that for the foreseeable future.