To go to ground means to hide, especially to escape from somebody who is chasing you which is depicted here that if they get a hint of the speaker being there, they will hide and try to escape, which will lead to the speakers failure.
Consider the staetement "We also need to do this quickly, because if they get a hint of us being here they will hide and escape and we will fail.". Based on this statement, is "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." a true statement? Yes/no/unknown