How many coins you are planning to buy..? which you think will make some kinda noticeable spike in price..!
Just happened.
Was that you who took ~250 BTC at around $427?
If so you will be happy to know that you never caused a spike in price. Less than 20 BTC have since been sold at prices between $427 - $432.29. Doesn't really look like there are many other buyers piling in either so you can sleep well knowing that you aren't burning any poor shorts.