IGN has special video for dead space 2 achievements.
In this video it will show you how to get "My boom stick","going for distances" ,"taste of your own medicine","c-section" ,"elevator action"(this is a secret achievement) and "collect peng"
But we're here for the "c-section" achievement. Its pretty easy achievement to get all you have to is buy the "contact beam" for 11,000 credits and buy one pack of ammo just in case you mess up. Find a slasher and quickly use the alt-fire(RT+RB) to knock it down and quickly charge up and discharge the beam before the slasher gets back up.