Fun facts the two wands Vincent has is a wand of Charm Person, and a wand of Summon Monster I. Nether of which spell descriptions include blows off targets arms. You should make a bluff check next time you threaten to blow someone's arm of with those  ;D. Also the probability of Shurkroat hitting an AC of 12 is 75%, and the statistical average of 3d8+7 is 20.5 damage. Just be careful if this escalate this any further. Math hurts and one hit could kill you.