BioWare’s yanked PS3 players hopes back down to earth, saying that “the Unreal Engine is cross platform, hence the PS3 code. This was brought up back in Mass Effect 1 days as well.” Thanks, Soong.
Source:http://www.vg247.com/2010/02/03/hey-you-got-your-ps3-in-my-mass-effect-2-source-code/