There are three stages of Ignika’s colour, the gold, when everything is nice and cool, silver, when the countdown begins and black, when basically everything in the MU is shutdown.
So why didn’t the Ignika basically killed everyone when Matoro failed in The Kingdom alternate universe?
When the mask’s countdown ends, it kills every living thing inside the MU. Since Mata Nui dying made the MU uninhabitable and everyone emigrated to the surface, they presumably all made it out before the mask’s countdown ended.
Maybe, but on the other hand, would’t it affect the Red star as well, as it was a complimentary structure to the robot. Beside Teri remained alive inside, though no mention of the syglaks survived. On the other hand maybe there was written, that not everybody was able to make it out, maybe the countdown got them.
According to BS01 (though uncited), the Ignika was locked away on Mata Nui (i.e. outside the GSR) after the Great Spirit’s death in the Kingdom Universe. If the mask was brought outside the robot before its countdown ended, the countdown would never have finished (like how the mask turned gold and its countdown stopped when Teridax ejected it from the GSR in the main timeline).