Correct use of and will spell your victory or defeat not only in teamfights, but in the game as well.
So if you get hit by her she will then land behind you.
As a note, watch when you use it.
If you listen to the build and stats displayed above, you will grow your win rate significantly and be closer to League of Legends pro players.
That way they are unable to proc their and are already going to be below half by the time they can proc it.
This means that when you land Blitzcrank's hook and then ultimate the enemy will be slowed so it will be harder for them to escape.