Caution: Achievement may be bugged for some. Haven't seen a solution to that yet, if I do I'll post it.
Story related, unmissable.
You will earn this achievement during your second visit to Arcadia after visiting the Farmer's Market to collect the items required for the Lazarus Vector. Follow the arrows back to Langford's Lab and, if you haven't already done so, create the vector solution in the U-invent in the office. (Bonus tip: Hack the U-invent to lower the cost of the solution).
You will be directed to install the vector in the air filtration system, but be careful as you will be attacked by three waves of splicers when you do. If you did not destroy the turrets or security camera during your first visit to the lab then you can hack them and they will assist you with the splicers. Once you have repelled the splicers, return to the location you installed the solution and flick the switch. This will unlock the achievement and progress you into the next phase of the story.