Case Searches by Minutes Elapsed

Since NetSuite's Case Escalation rules for "Duration since Case Creation" or "Creation Time" are only based on hours elapsed and not minutes. 

I'm trying to build a search that alerts users when a P1 priority case comes in that hasn't been touched in 15mins or more.

So I've been trying to build a search using the formula where "Incident Date (ID:startdate)" or Created Date (ID:createddate) is greater the {sysdate} of 15mins.  But I have no idea how to parse out the "Time values" out of the "startdate" or "createddate" date fields to build my formula.

Then on the flip side, when we respond to a P1 case.  I'm looking to track the cases where we haven't heard from the customer in 30mins or more.  Again there is standard NetSuite Case Escalation rule for this "Duration since Last Modified by Customer" but it only works for hours and not partial hours.