#2 Betrayals
Even though Superstars from each brand will unite to take on those from the other two brands, it doesn't mean that they will remain on the same page or there won't be any internal conflict. For example, Roman Reigns and King Corbin, two Superstars who don't get along, will be on the same team.
Corbin is the only heel on Team SmackDown, and he has/had issues with all of his teammates. He could possibly turn on them by attacking Roman Reigns after getting eliminated or he could get Reigns eliminated instead, furthering their feud in the process. Corbin doesn't care if his team wins or not.
The only thing he cares about at the moment is taking care of Roman Reigns. The same could happen on Team RAW. Randy Orton teamed up with Ricochet on RAW this week to take on the Viking Raiders for the RAW Tag Team Championships. Perhaps Orton joined forces with Ricochet so that he could get the latter to trust him.
Orton is just waiting for the perfect time to strike. In the end, he is still a viper, and that's what vipers do. As Jake 'The Snake' Roberts once said, never trust a snake. Orton could RKO Ricochet 'outta nowhere' once again, revealing his true colors. He has turned on so many people in the past, and he could so again this Sunday.