Hello,
my two girls did make a dash for it at first, (they are not very old and not sisters), but then I thought about letting them know what I was intending to do, such as picking them up by snapping my fingers. It seems to work, so give that a try before they start to run. When replacing them the finger snapping is done as well.
The other thing that appealled to me was to block the ramp to they can not run down before I go to pick them up and snap my fingers. Good luck and let us know how you get one. Byeee