Put it this way, if my family were on the Helios flight, I have enough evidence to take Boeing to the cleaners under a product liability suit!
Well lets review the facts: Errors on panel scan and O2 mask check. Ignoring warning horn and attempting to disable it by pulling c/b. Ignoring indications of higher than normal cabin climb rate(ear discomfort, cabin climb indicator). Ignoring unusual wind noise from cockpit windows due to unpressurized flight. Ignoring rubber jungle in cabin and reports from F/A's of ear discomfort and cold cabin air. Ignoring lack of airflow and lack of normal noise from packs in cockpit. Ignoring cold temperature in cockpit. Leaving your position during a suspected abnormal situation etc.
Sue the manufacturer?