@Windyridge , this is the official rule for using a hero dice.
A hero die is a free, one-time reroll and, unlike karma, can be used on natural 1s. Five karma points can be used to get another hero die..
You can, however, use karma on the higher roll because the 1 is not your number; a boon means you use the higher of the two.
Also, I didn't envision Grimbsly striking the lock...I thought he was going to use the crowbar the way its designed to be used but thats just IMO lol.
OOC:
So, @Windyridge , if you agree to subtract 2 hero die from your character sheet, I'll agree to let the 6 stand as a success. If not, add +1 Karma to your sheet. We wait for your response