Thankfully, even though Borg weaponry produced traces of gamma radiation, the cube he was describing sounded nothing like that which the hive mind had produced. Alerting the Borg in this century/timeline to her (considerably more advanced) presence was a constant concern, and she ran daily diagnostic checks on herself to ensure that her proximity transceiver had not managed to reasserted itself.
"I take it this Tesseract is intended to act as a power source."