Tiona had a good memory, so she was able to pinpoint the exact location of the City Lord's Residence even if she was digging under the ground alongside Rocky.
The Rocky Bal-Boa was there to help protect her just in case something went south.
It was still a Rank 5 Monster known for its toughness, so escaping with Tiona was not a problem.
If the Champions really wanted to run after it, they would have to have a powerful digging ability that could outrun it in its own environment.
"Remember Tiona, no matter what happens, don't enter the Residence. Just try to find if there is anything suspicious from a safe distance. Prioritize safety above all."
That was the reminder that Thirteen told the Black Snake before she left to do her mission.
Because of this, she remained at a safe distance and merely extended her senses to get a better understanding of the layout of the residence.