#4 Aiden English helps Rusev win
When Simon Gotch and WWE decided to part ways, Aiden English's future seemed quite uncertain. It did seem for a while that he would get lost in the shuffle. Thankfully, he aligned himself with Rusev and 'Rusev Day' has become the hottest act in WWE. In addition to his deep voice, English also lends Rusev his fists.
While Rusev pinning The Undertaker all by himself may be a bit of a stretch, we can totally imagine English and Rusev teaming up to take The Dead Man out. The two of them could load him up into a casket for Rusev to secure a victory. And this could help Rusev rise the main roster rungs.
The numbers game is the only plausible scenario we can imagine where The Undertaker suffers a loss. Even if the contest were to be lopsided, it would be a pretty big win for the Bulgarian Brute.