Fix #11166: Null pointer read in Guest::UpdateRideAdvanceThroughEntrance (#11182)

src/openrct2/peep/Guest.cpp

@@ -3728,9 +3728,18 @@ void Guest::UpdateRideAdvanceThroughEntrance()
     }
 
     Vehicle* vehicle = GET_VEHICLE(ride->vehicles[current_train]);
+    if (vehicle == nullptr)
+    {
+        return;
+    }
+
     for (int32_t i = current_car; i != 0; --i)
     {
         vehicle = GET_VEHICLE(vehicle->next_vehicle_on_train);
+        if (vehicle == nullptr)
+        {
+            return;
+        }
     }
 
     ride_entry = get_ride_entry(vehicle->ride_subtype);