User blog comment:Crystar800/New Map, New Wiki, Same Goals/@comment-24001421-20131021024625/@comment-5908594-20131021041552

Safeguard is different. It's more like MW3 Survival. This "Extinction" mode seems to be different. The achievements mention electric traps and ancient relics and stuff of the sort. TMartn is the one who speculated it was an alien game mode among others.