Developer BioWare has been pulling the wool over the eyes of fans for more than a decade, convincing gamers through clever technical tricks that they were going fast when, in fact, they were not. The veil was lifted after Dragon Age Inquisition's "horse sprinting" was revealed to be an illusion, and now it seems that Shepard never actually moved any faster on the Citadel, either; you just thought they did.
Eurogamer has been on the bleeding edge of this one, noting as former BioWare veteran John Ebenger dropped truth bombs on Twitter. In the original version of Mass Effect (released in 2007, coming to PS3 in 2012), technical limitations prevented the game from loading any faster, so a change to the camera was made to give the illusion of moving faster: "Same thing in Mass Effect 1 when you try to run on the Citadel. No change in speed, just in the FOV of the camera to give the illusion you're moving faster. Can't remember if that stayed true for 2 and 3 or if load times were better by then."