Plug Depth
Plug depth designates the proximity of the entry plug, or its internal array, to the Eva's core. The concept is present in Neon Genesis Evangelion, but is expanded upon and more heavily utilized in Rebuild.
In the Rebuild continuity, the internal array of the entry plug, upon which the pilot is seated, can move up and down the entry plug on a track, closer to or further from the core unit, depending on various conditions. Moving too close results in a negative value (i.e., exceeds the acceptable zero depth), which, according to Nerv's staff, threatens the humanity of the pilot.
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