Variable for extension CID, not trunk or outbound route CID

I got some dial plan code in extensions_custom.conf to send me emails whenever a 911 call was placed. In the body of the email I would like to see the name and CID of the local extension that placed the call. However ${CALLERID(NUM)} is using the CID of the trunk or the outbound route.
Is there a variable that would give me the CID of the extension or some other way to accomplish what I want?

exten => s,1,ExecIf($["${OUTNUM}"=“911”]?System(echo “A 911 emergency call was just placed from extension ${CALLERID(NUM)} - ${CALLERID(NAME)} on ${STRFTIME(%C%m%d%y%H%M)}” | mail -s " 911 Alarm from ${CALLERID(NUM)} - ${CALLERID(NAME)}" [email protected]))
exten => s,n,MacroExit()

Add DumpChan() to your context, use whatever useful that is exposed. You can use that info to lookup /AMPUSER/ext in the asteriskdb for more detail