No back-to-back MTOs. If you want one, give up a game or a point a minute. Bad luck if it is legitimate. I find it hard to believe that top-class athletes would be playing with (or have them crop up during a match) multiple conditions when they are so fit and well-conditioned and travel with trainers and physios and what not.
I saw a player at a women's challenger in Salt Lake City (about 10 years ago) come down from an overhead and roll her ankle. When she fell down, she badly injured her wrist. Even though it happened at the same time, it's still considered 2 injuries.