Congratulations on the RATN! Your comment made me laugh - my sister-in-law is training her Malinois for SAR. She told me that one of the members of their SAR group has a cap with "Trust the dog" embroidered on it. It's hard to not make assumptions about things but the dogs are unencumbered by our predisposition to worry that we found things too quickly.
Since I volunteered as a rat wrangler I learned a lot!
1. Too many people are talking (find it, look here, tunnel...)and not paying attn. to their dog. Many times once the dog finds it and the handler isn't paying attn. they won't go back to that spot because they believe they already showed the handler where the rat was.
2. My dog DOES have a signal, 2 in fact, sometimes she points and sometimes she pounces, BUT on our first trial run she did neither and just kept going back to the same spot so I called it. IF YOUR DOG KEEPS GOING BACK STOP REDIRECTING THEM!!! So many times this one happened because the handler thought they knew where the rat was and called it wrong.