diff --git a/lua/server/room.lua b/lua/server/room.lua
index 57a1f103..bb649f9c 100644
--- a/lua/server/room.lua
+++ b/lua/server/room.lua
@@ -1475,12 +1475,13 @@ function Room:damage(damageStruct)
   assert(type(damageStruct.to) == "number")
 
   local stages = {
-    [fk.PreDamage] = damageStruct.from,
-    [fk.DamageCaused] = damageStruct.from,
-    [fk.DamageInflicted] = damageStruct.to,
+    {fk.PreDamage, damageStruct.from},
+    {fk.DamageCaused, damageStruct.from},
+    {fk.DamageInflicted, damageStruct.to},
   }
 
-  for event, playerId in ipairs(stages) do
+  for _, struct in ipairs(stages) do
+    local event, playerId = table.unpack(struct)
     local player = playerId and self:getPlayerById(playerId) or nil
     if self.logic:trigger(event, player, damageStruct) or damageStruct.damage < 1 then
       return false
@@ -1500,12 +1501,13 @@ function Room:damage(damageStruct)
   end
 
   stages = {
-    [fk.Damage] = damageStruct.from,
-    [fk.Damaged] = damageStruct.to,
-    [fk.DamageFinished] = damageStruct.from,
+    {fk.Damage, damageStruct.from},
+    {fk.Damaged, damageStruct.to},
+    {fk.DamageFinished, damageStruct.from},
   }
 
-  for event, playerId in ipairs(stages) do
+  for _, struct in ipairs(stages) do
+    local event, playerId = table.unpack(struct)
     local player = playerId and self:getPlayerById(playerId) or nil
     self.logic:trigger(event, player, damageStruct)
   end
diff --git a/packages/standard/init.lua b/packages/standard/init.lua
index 96f7fa90..11a30afb 100644
--- a/packages/standard/init.lua
+++ b/packages/standard/init.lua
@@ -21,22 +21,22 @@ local fankui = fk.CreateTriggerSkill{
   events = {fk.Damaged},
   frequency = Skill.NotFrequent,
   can_trigger = function(self, event, target, player, data)
-    return target:hasSkill(self.name)
+    local room = target.room
+    local from = room:getPlayerById(data.from)
+    return from ~= nil and
+      target == player and
+      target:hasSkill(self.name)
   end,
   on_trigger = function(self, event, target, player, data)
-    local damage = data.damage
     local room = player.room
-    local from = room:getPlayerById(damage.from)
-    if event == fk.Damaged then
-      if from:isNude() then return false end
-      if room:askForSkillInvoke(target, self.name) then
-        local card = room:askForCardChosen(target, from, "he", self.name)
-        room:obtainCard(target.id, card, false, fk.ReasonPrey)
-      end
+    local from = room:getPlayerById(data.from)
+    if (not from) or from:isNude() then return false end
+    if room:askForSkillInvoke(player, self.name) then
+      local card = room:askForCardChosen(player, from, "he", self.name)
+      room:obtainCard(player.id, card, false, fk.ReasonPrey)
     end
   end
 }
-
 local simayi = General:new(extension, "simayi", "wei", 3)
 simayi:addSkill(fankui)
 Fk:loadTranslationTable{