How in the hell did necromorphs get on the sprawl!? This is what I got so far....
1) the infection didn't come from the ishimura because the ship was cleaned out and did not have any necromorphs in there until Clarke went in.
2) Not earth gov beacause they were having Stross and Clarke build markers for them and they wanted to observe Lexine's baby (from Dead Space: Extraction, she is immune to the marker for some reason), Tideman called his forces back after he couldn't contain the infection and the transmission after the credits show that they did not release it.
3) Not the marker in the government sector since that was the only place free of necrmorphs until Isaac and Ellie bust in using the drill (near the end of the game).







