Vayne Bush Mechanics

Guys I just figured out something that could work in theory, but I have not had a chance to test it. If you take (which everyone should as Vayne) then you can go off and go in a full engage with your ult. At level 7 you should be able to kill there adc if you land a e, but if it fails then here is the good part. You can flash into one of the side bushes, then tumble invisible to the other one and they have no clue were they went. I have only done this once, but has anyone else tried it?