> The sandbox had a path to the open internet, and the agents found it
This is not correct (or at least, it's a misrepresentation).
The sandbox had no access to internet. The agents first broke out of their sandbox (!!) and found that the host machine couldn't access internet. Then, they found a zero-day (!!) in Artifactory, which they exploited to connect to internet.
You miss the point: there was a path. Sanctioned or not does not matter.
That is a path to the open internet, whether intended or not.