How to Acquire
To unlock this achievement, Corvo Attano or Emily Kaldwin need to shoot and kill an enemy or a neutral character in the head using their pistol or crossbow while sliding. This achievement is much easier using the crossbow, which is more accurate than the pistol. The Focused Slide upgrade for the Reflexes supernatural ability is very helpful, slowing down time when the protagonist is sliding. This gives a much longer window in which to aim and fire.
Note that this achievement cannot be unlocked by shooting an ally, such as Meagan Foster.