Achievement text: "Survive an attack due to the energy shield augmentation."
You need to survive an extreme amount of damage with the Energy Shield augmentation for this. I got this with the shields at level 2, having Simons unload into me with his plasma rifle. I had to pop a lot of medkits and energy cells to stay alive and keep the shield up. I took around 5 back-to-back direct hits.
The unlock check is done with the shield is deactivated, which also happens when you die. Simons killed me, and the achievement popped as I died.