To display repeater data in a formatting field there are a number of steps required.

First you need a SQL Report.  See below example of repeater with single field.  Replace any x's with relevant field numbers and applicationID etc.

SELECT RepeaterXMLFieldx.DataXMLFieldx.value('./Data[@DatabaseValue="TextFieldx"][1]/@Value','nvarchar(max)') as 'Repeater Field' FROM Claims WITH (NOLOCK) Cross Apply XMLFieldx.nodes('//RepeaterData/Repeat') RepeaterXMLFieldx(DataXMLFieldx)  
  WHERE ISNULL(Claims.Archived,0) = 0 AND ApplicationID=x AND Claims.ID=[!InputItemID!]

To test the report temporarily replace [!InputItemID!] with a real Item ID.

Then publish the report so it is selectable in the next step.

Create a WikiPage

Create a WikiPage and select the report from the Reports menu to add it to the WikiPage.

Publish the WikiPage.

Go to Form Designer and Create Formatting Field

Go to formatting field settings and change it to type wiki page.  Then select wiki page.

Test in a record with some repeater data.

Notes

The data has to have been saved for it to appear in the section.