diff --git a/dbtmetabase/_exposures.py b/dbtmetabase/_exposures.py
index 842a2d5..2feca9c 100644
--- a/dbtmetabase/_exposures.py
+++ b/dbtmetabase/_exposures.py
@@ -140,7 +140,7 @@ def extract_exposures(
                         f"Visualization: {entity.get('display', 'Unknown').title()}"
                     )
 
-                    result = self.__extract_card_exposures(ctx, card=entity)
+                    result = self.__extract_card_exposures(ctx, entity)
                     depends.update(result["depends"])
                     native_query = result["native_query"]
 
@@ -168,12 +168,9 @@ def extract_exposures(
                         if "id" not in card:
                             continue
 
-                        depends.update(
-                            self.__extract_card_exposures(
-                                ctx,
-                                card=self.metabase.find_card(uid=card["id"]),
-                            )["depends"]
-                        )
+                        if card := self.metabase.find_card(uid=card["id"]):
+                            result = self.__extract_card_exposures(ctx, card)
+                            depends.update(result["depends"])
                 else:
                     _logger.warning("Unexpected collection item '%s'", item["model"])
                     continue
@@ -231,11 +228,7 @@ def extract_exposures(
 
         return exposures
 
-    def __extract_card_exposures(
-        self,
-        ctx: __Context,
-        card: Optional[Mapping],
-    ) -> Mapping:
+    def __extract_card_exposures(self, ctx: __Context, card: Mapping) -> Mapping:
         """Extracts exposures from Metabase questions."""
 
         depends = set()
@@ -251,14 +244,11 @@ def __extract_card_exposures(
 
                 if str(query_source).startswith("card__"):
                     # Handle questions based on other questions
-                    depends.update(
-                        self.__extract_card_exposures(
-                            ctx,
-                            card=self.metabase.find_card(
-                                uid=query_source.split("__")[-1]
-                            ),
-                        )["depends"]
-                    )
+                    if source_card := self.metabase.find_card(
+                        uid=query_source.split("__")[-1]
+                    ):
+                        result = self.__extract_card_exposures(ctx, source_card)
+                        depends.update(result["depends"])
                 elif query_source in ctx.table_names:
                     # Normal question
                     source_table = ctx.table_names.get(query_source)
@@ -273,14 +263,12 @@ def __extract_card_exposures(
 
                     if str(join_source).startswith("card__"):
                         # Handle questions based on other questions
-                        depends.update(
-                            self.__extract_card_exposures(
-                                ctx,
-                                card=self.metabase.find_card(
-                                    uid=join_source.split("__")[-1]
-                                ),
-                            )["depends"]
-                        )
+                        if source_card := self.metabase.find_card(
+                            uid=join_source.split("__")[-1]
+                        ):
+                            result = self.__extract_card_exposures(ctx, source_card)
+                            depends.update(result["depends"])
+
                         continue
 
                     # Joined model parsed