By the power of truth, I, while living, have conquered the universe.
Posted by: King Nis085
I don't think MB was behind the portal closing in on the Chief - there's no physical way he could have.
Not entirely true.
When the Halo Rings are shown above the Ark in Origins, they all head into the slipspace portal. This confirms that multiple objects in slipspace are not simply sent on a 1-way vector because each of the Halos end up in different locations. So it is therefore logical to conclude that it was very much possible for Bias to send half the Dawn to Earth and the other to the Legendary Planet.
I believe it is stated in one of the Terminals the Bias infiltrated the portal's systems, so he has a degree of control over it.
[Edited on 07.21.2011 11:40 AM PDT]