The best way to get this is to use the following loadout:
Scout:The Force-A-Nature
The Crit-A-Cola
The Atomizer
Then, before the round starts, go to the front line and find one of these containers:
http://imgur.com/bjvXkPBFirstly, jump over the crate using the Force a nature's knock-back mechanic. If you're not sure what this is, you need to jump, then shoot the ground to get extra height. Using the atomizer, you can do this after your 3rd jump to get you over.
As soon as you get over, drink the crit a cola, then kill someone. There will usually be players waiting in the next area.