So we're dealing with a 3.6 (Suppression) hearing, not a 3.5 (Confession) hearing?
If your lawyer does not believe that a witness's answer is adequate, your lawyer can ask him additional questions to obtain additional facts. Nothing you have posted suggests that the witness was dishonest.
If the defendant was there, the defendant knows what happened and thus should be able to help his lawyer prepare for a hearing. You have not indicated how the information that the officer didn't volunteer at the hearing would affect the outcome of the case.

