This can be done throughout the game and there are lots of opportunities
to get this achievement.
First of all, the door needs to be locked
, you need to press the
button in order to kick the door open. once the door has been kicked you'll need to kill and enemy within 2 seconds of you kicking open the door. I would recommend either a Shotgun or an SMG
When going into areas with enemies, make sure to press the
button. This will allow you to easily spot
enemies around you.