If there is something disturbing one’s concentration during shemoneh esrei that he/she can do something about, then between berachos, one may step away (no “three steps back” first), and do what needs to be done (e.g. disconnect the telephone, pick up the fallen sefer, etc.) and then return to his/her original place and continue davening.
If a child is crying, and there is no aytza to get the child to stop, one may move to another place and continue. If he/she decides to try to placate the child, one may do so with motioning only (give the kid some candy!…ok. ok, carrot sticks – but don’t blame me if the kid doesn’t stop crying), without talking.