Here's a sym tech that nobody seems to know or use:
Place your turrets BEHIND a wall/obstacle (not on the ground) and then place your teleporter. Your turrets are protected and the enemy has no idea what you're up to 
pic.twitter.com/jKnmHwuhyH
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Here’s another „pro tip“: stick your turrets on the wall and place your Shield wall directly in front of it. So enemy’s can’t stand between the shield wall and the actual wall and therefore: can’t destroy the turrets.
