EI: s10 fix owaec being able to enter the sanctuary (#8850)

Fixes #8843

data/campaigns/Eastern_Invasion/scenarios/10_Dark_Sanctuary.cfg

@@ -923,7 +923,6 @@ The darkness between worlds opens its maw."
     [/event]
 
     # Owaec refuses to enter the outer lock
-    # this is good for flavor, but also helps with balance. Vanguard + Baneblade would be way too strong
     [event]
         name=enter hex
         first_time_only=no
@@ -938,7 +937,30 @@ The darkness between worlds opens its maw."
             speaker=Owaec
             message= _ "I will not aid in this evil quest."
         [/message]
-        {MOVE_UNIT (id=Owaec) $x2 $y2}
+        # prevent blocking Owaec to force him into the sanctuary
+        [if]
+            [have_unit]
+                x,y=$x2,$y2
+            [/have_unit]
+            [then]
+                [store_unit]
+                    [filter]
+                        x,y=$x2,$y2
+                    [/filter]
+                    variable=stored_forcepush
+                    kill=yes
+                [/store_unit]
+                {MOVE_UNIT (id=Owaec) $x2 $y2}
+                [unstore_unit]
+                    variable=stored_forcepush
+                    find_vacant=yes
+                [/unstore_unit]
+                {CLEAR_VARIABLE stored_forcepush}
+            [/then]
+            [else]
+                {MOVE_UNIT (id=Owaec) $x2 $y2}
+            [/else]
+        [/if]
     [/event]
 
     # Dacyn cycles the outer lock