The _audit index is not the place to find this information. The _audit index can be used to see if alerts triggered as they should, but there is nothing in the audit index that contains the actual search results of the triggering search. In general, the _audit index should not be used as part of the alerting mechanism.
If you want to take an action based on the results of a search, you should edit the saved search itself. As part of the saved search, you could select the fields that you want to appear - and include the search results in an email for example.
If you want more follow-up on this, please show the original search that caused the alert to trigger.