Note, this Achievement is slightly glitched. PlayStation Trophies has documented this (link below) and I can confirm from my own playing experience that the issue is the same on Xbox.http://www.playstationtrophies.org/forum/overwatch-origins-e...
Glitch Warning: There are reports that this trophy is unobtainable if playing as D.va so pick another character when you go for it.
This trophy can be very luck dependant. You will first of all need to play in a game where the opposing team has a Symmetra and after that pay attention to the voices of the characters on your own team and they will inform you that there is an "enemy teleporter located or "enemy teleporter nearby". The teleporter is a device (Symmetra's ultimate) that can be placed anywhere on the map and will teleport players from their spawn to the teleporter location. Good players will place these in very hard to find spots, so keeep a look out if you hear the characters talk about it.
As mentioned, when I played as D.Va on Xbox against a Symmetra that set up 3 teleporters it wouldn't unlock. Can't make a comment on any other character but if you see an opportunity to unlock this in a Quick Match then I recommend switching away from D.Va.Update:
Blizzard have fixed the bug that prevented D.Va mechs from unlocking this: