I was told (CFM-56 at that time) the LP spool will give you airframe shake, unlike the HP where indication without perceived vibration needs to be taken into account straight away.
tdracer, does that resemble any of your experience?
Indeed, anything we're allowed to do in commercial air transport is based on the n-1 scenario, taking idle thrust and following the trajectory for EO is always a safe (enough) option. Some choices are less optimal than others (e.g. the 737 divert to Iran) but on a bad day you might need to take them.