Honeypot and hack the FBI using the same warrant.
Based upon the wording, it sounds like it would be legal to honeypot (bait) the FBI and hack them using the same backdoor connection, which was "authorized" by the same warrant.
The definition of a honeypot is that there is no legitimate traffic, and all is subject to deep packet forensics and scrutiny.
Bonus points if the determined endpoint is the Chinese embassy located in the United States.