User blog comment:So-Pro Warrior/Special Sneak Preview of Season 2: Battle of the Ultimate Galaxy Savers: Master Chief vs. Commander Shepard/@comment-5931345-20130613105258/@comment-4541447-20130614044121

You know just saying that Chief HAS gone into combat without Cortana before and come out alive. For Example if you watched the Miniseries Halo 4 Forward Unto Dawn for example and during the early years of his time in the Human-Covenant War as well as the beginning of Halo 3. So just because he doesn't have Cortana doesn't really mean a lot. He has shown that he can fight without her he doesn't become weakened in any sort of way.