Critical Wounds , Redux and Open Ambushing Questions

[Hlendril]

A few hours ago I was hunting Frost Giants when I was struck by one of its Major Cold spell. I suffered 25 damage and had a rank 3 wound to my neck which should have killed me, yet it didn't. How is this so, when Critical wounds in the neck and head usually translates to a instant death?

Another question in mind is Redux. I don't know if its a proper question to be asked but does Redux work on magic based damage, such as warding damage?

And last is open Ambushing. I`m trying to work on my ambush skill a bit after I migrated most of my skill points in Armour Use and Physical training. I read somewhere that Ambushing adds additional weighing to my attack. I am using a Claidhmore as my weapon so does the additional weighing on a Ambush attack is also added to the Claidhmore or only hidden Ambush grants additional weighing to an attack, not Open Ambush?

[Zarston]

The lethality of critical hits are based on the type of damage. If you look on the critical table for ice (https://gswiki.play.net/Cold_critical_table), you'll see that you can have a non-fatal Rank 3 wound with a Rank 5 crit.

Redux does not protect you against warding based damage.

The additional weighting on an ambush attack is only applied to attacks from hiding. Training in Ambush does help you aim your open melee attacks however. Testing seems to suggest that you only need around 24 ranks in Ambush to maximize aiming your attacks from the open.