User blog comment:Suparockr/List of Plotholes throughout the series/@comment-6810992-20130301002900/@comment-24174486-20130301024601

"Why is Anderson on the citadel? how did he get there? through the same beam of light? but he wasn't behind you right? ok... so it may have been the same beam of light... so why is he on another totally different part of the citadel? hmm... oversight?"

In addition to Anderson's own words (that he believes they popped up in different areas in the Citadel), he also mentions that the Citadel is shifting and rearranging.

"red... right, through all three games red is RENEGADE. do not choose that one!! green... hmm... cowards way out... nah, ill choose blue, which MUST be paragon, as we have been forced to believe throughout 90+ hours of gameplay..."

Because the colour-based representation of morality in the game's user interface applies in the actual Mass Effect universe itself.

If that were the case, Shepard would invariably be a Renegade based on the red stripe on their armour.