Star Trek Picard: Every Easter Egg & Hidden Reference From 'Broken Pieces'
11. The Next Regeneration
Seven leads Elnor to the Queen's cell and starts to reactivate the dormant cube. The normally subdued blue lighting in the Artifact turns green which was the prominent color aboard Borg cubes as they appeared in Star Trek: Voyager.
Whatever Seven is doing, the cube begins regenerating. In the frequently referenced first appearance of the Borg in "Q, Who?", a cube is seen mending itself after suffering severe damage from the Enterprise-D's weapons. In "Broken Pieces", this regeneration is depicted as small, green-glowing, bug-like drones swarming over and repairing the damaged portions of the ship.
As the cube begins to wake up, Narissa recognizes the threat from Seven and the Borg drones still in stasis. She mulls gassing or electrocuting the Borg, before settling on jettisoning them into space. Borg were jettisoned into space in the Star Trek: Enterprise episode "Regeneration" (which highlighted a lot of the regeneration process).
The Borg were also seen in the vacuum of space in the movie Star Trek: First Contact, where they actually seemed to be okay hanging out on the hull of the Enterprise...