How to get the value of an element inside escaped XML?

Summary

How to get the value of an element inside escaped XML?

Content

Is there an XPath expression that gets the value of an element from escaped xml?  I am aware of an approach using parseEscapedXml(), xsl:copy-of, and xsl:variable to accomplish the task, but I want a way to do this natively in the ICS UI without importing the xsl transformation.

The input payload contains an escaped xml string in the EventData element.  I’m interested in an XPath Expression that gets the person_id value out of the escaped xml string.

Here is the sample payload.

<BusinessEvent_Input xmlns="