I actually wonder...since she’s always trying to oppose the villainess system, the system gave her tasks that was increasingly hard to avoid. Right here, before the future Elsa/system Elsa(?) arrive, I was seriously hoping that which ever kind of fall Yvonne chose, she would use wind magic or fall from like, three steps. Falling down a flight of stair is no joke and with the extra added weight, you could get seriously injured.
I was hoping for the use of wind magic to cushion their fall or something but what if that’s not possible or Yvonne didn’t use that and these stairs were the start of many of her more serious injuries while trying to trick the system to protect her family and to protect Elsa. That’s when Future Elsa started to intervene and make some major plot changing options appear.
I also feel that Future Elsa won’t be able to do it all the time...just a guess.