MB 3: Between one and the other - In the book Shulchan Shlomo, it says that so too if one completed the Eighteen Blessings, even though he has not yet moved back, and recalled that he made a mistake and must go back, then he should wait.
MB 4: Long enough to walk four amos - Even if one does not want to step forward again, but rather intends to pray the second time in the place where he is now standing after backing away from his first prayer; [because] in order to return to one's place one must wait even if he does not intend to pray a second time, as we will see in Siman 123.