Stalemate Resolution Annex
From the Portal Wiki
"...unless a stalemate associate is present to press the stalemate resolution button."
"Stalemate Resolution Associate: Please press the Stalemate Resolution Button."
The Stalemate Resolution Annex is an area located inside the Central AI Chamber where the Stalemate Resolution Button resides.
A Stalemate Associate, or in this case, Chell, is needed to press the Stalemate Resolution Button if there is any case of either core, either the corrupted core or the substitute core, disapproving the core transfer protocol. If the button is pressed, the core transfer will begin, irregardless of the conditions of both cores. Humorously, only a "trained stalemate resolution associate" is permitted to press the stalemate resolution button.