At the moment, vindication makes for cold comfort, and Cortana spends a few nanoseconds of the time between York's warning and Sombra's reaction considering her options. The conclusion she reaches could reasonably be described as 'foregone.'

As the tendril starts to pull free of the wall, Cortana does the digital equivalent of slapping a breaching charge on the bunker door of Delta's counter-intrusion protocols. The need not to kill either Sombra or York in the process complicates matters, and she suspects the fight will last longer than she'll be happy admitting to after the dust settles, but she doesn't harbor even a flicker of doubt about the outcome.

DELTA!