OoC: I think the 50/50 chance for Jeb's scroll takes place when Eric gets hit and not during the casting. It stuns the damage giver. It's like the reverse if Dreyrugr's blade.
Scroll of Ice Armour Coats player’s armor in a layer of ice for one battle at the cost of 5 ether. Enemies have a 50/50 chance of being frozen(stunned) in place for the next round after player rolls damage or special damage. Damage and effects done by enemy are calculated before the freezing effect.
"It should coat Erik's armour in ice. I'll repeat."
(or, if I'm right, and it's automatic:)
I'll fire my bow from the backrow.