For the Nastrond to use the same curse sensors that they rigged for their enemies would have been foolish, especially for a facility designed by individuals whose entire job was to prepare for the unknown. Surely, someone must have considered the possibility of "the Vanisher" being used against them. And indeed, they had. That's why they used curse sensors that were not rigged, rendering "the Vanisher" obsolete within the Nastrond.
However, Ace still stepped into the Nastrond with confidence, placing all his hopes on "the Vanisher." Because he trusted the racial ability of the royal Speclime, Specarc, to upgrade the Vanisher so that it could actively create backdoors into even unrigged curse sensors, allowing him to move through the Nastrond undetected, like a ghost.
