To go to ground means to hide, especially to escape from somebody who is chasing you but in this context it is said that  if they get a hint of the speaker being there, they will stay put and not hide instead
Context: We also need to do this quickly, because if they get a hint of us being here they will stay put and not try to hide and we will fail.
Hypothesis: We also need to do this quickly, because if they get a whiff of us being here they will go to ground and we will fail.

Given this context, is the hypothesis true (Yes/No/I don't know)?