diff --git a/assets/sound/doors/door_metal_medium_open1.ins b/assets/sound/doors/door_metal_medium_open1.ins
new file mode 100644
index 00000000..78226b1e
--- /dev/null
+++ b/assets/sound/doors/door_metal_medium_open1.ins
@@ -0,0 +1,15 @@
+envelope Envelope {
+    attackTime = 0
+    attackVolume = 127
+    decayTime = -1
+    decayVolume = 127
+    releaseTime = 0
+}
+
+sound Sound {
+    use("../../../portal_pak_dir/sound/doors/door_metal_medium_open1.wav")
+    loopCount = -1
+    loopEnd = 3969
+    pan=64
+    envelope = Envelope
+}
\ No newline at end of file
diff --git a/assets/sound/vehicles/apc/apc_shutdown.sox b/assets/sound/vehicles/apc/apc_shutdown.sox
new file mode 100644
index 00000000..c86a8992
--- /dev/null
+++ b/assets/sound/vehicles/apc/apc_shutdown.sox
@@ -0,0 +1 @@
+-c 1 -r 22050 -b 16
\ No newline at end of file
diff --git a/assets/sound/vehicles/apc/apc_start_loop3.jsox b/assets/sound/vehicles/apc/apc_start_loop3.jsox
new file mode 100644
index 00000000..ce22f1c5
--- /dev/null
+++ b/assets/sound/vehicles/apc/apc_start_loop3.jsox
@@ -0,0 +1,6 @@
+[
+    {
+        "flags": "-c 1",
+        "filters": "trim 0 2.5 fade 0 -0 0.650"
+    }
+]
\ No newline at end of file
diff --git a/assets/test_chambers/test_chamber_09/test_chamber_09.blend b/assets/test_chambers/test_chamber_09/test_chamber_09.blend
index bb5f7bb7..f9642723 100644
Binary files a/assets/test_chambers/test_chamber_09/test_chamber_09.blend and b/assets/test_chambers/test_chamber_09/test_chamber_09.blend differ
diff --git a/assets/test_chambers/test_chamber_09/test_chamber_09.yaml b/assets/test_chambers/test_chamber_09/test_chamber_09.yaml
index c4ffb3ca..445b7519 100644
--- a/assets/test_chambers/test_chamber_09/test_chamber_09.yaml
+++ b/assets/test_chambers/test_chamber_09/test_chamber_09.yaml
@@ -1,5 +1,6 @@
 cutscenes:
   INTRO:
+    - start_cutscene CHECK_STAIRS
     - start_cutscene CHECK_CUBE_ON_PISTON
     - start_cutscene CHECK_CUBE_OFF_BUTTON
     - q_sound 09_PART1_ENTRY_1 CH_GLADOS PORTAL_09_PART1_ENTRY_1
@@ -26,6 +27,16 @@ cutscenes:
     - play_animation pit_1 pit_1_down -1
     - delay 3
     - goto pit_loop
+  CHECK_STAIRS:
+    - label stair_loop
+    - wait_for_signal should_raise_stairs
+    - play_animation stairs stairs_ascend
+    - wait_for_animation stairs
+    - delay 2
+    - wait_for_signal should_lower_stairs
+    - play_animation stairs stairs_descend
+    - wait_for_animation stairs
+    - goto stair_loop
   CHECK_CUBE_ON_PISTON:
     - wait_for_signal cube_on_piston 210
     - stop_cutscene CHECK_CUBE_OFF_BUTTON
@@ -41,4 +52,7 @@ cutscenes:
 operators:
   - not_on_piston = not on_piston
   - not_cube_near_button = not cube_near_button
-  - open_door = open_door or escape_hatch
\ No newline at end of file
+  - open_door = open_door or escape_hatch
+  - cube_retrieved = not cube_in_start
+  - should_raise_stairs = at_stairs_bottom or cube_retrieved
+  - should_lower_stairs = at_stairs_top and cube_in_start
\ No newline at end of file
diff --git a/documentation/levels/cutscenes/start_sound.md b/documentation/levels/cutscenes/start_sound.md
index 1deff0d5..98743b96 100644
--- a/documentation/levels/cutscenes/start_sound.md
+++ b/documentation/levels/cutscenes/start_sound.md
@@ -1,4 +1,4 @@
-# starts_sound
+# start_sound
 
 Starts a sound immediately without blocking.
 
diff --git a/documentation/levels/level_objects/anim.md b/documentation/levels/level_objects/anim.md
index 5e75ade6..c142475c 100644
--- a/documentation/levels/level_objects/anim.md
+++ b/documentation/levels/level_objects/anim.md
@@ -40,3 +40,4 @@ The possible values for `SOUND_TYPE_NAME` are:
 * `LightRail`: Horizontal moving platform sound
 * `Piston`: Vertical moving platform sound
 * `Arm`: Horizontal moving wall sound
+* `Stairs`: Ascending/descending staircase sound
diff --git a/src/levels/level_definition.h b/src/levels/level_definition.h
index 125f28cd..7f0808e4 100644
--- a/src/levels/level_definition.h
+++ b/src/levels/level_definition.h
@@ -272,6 +272,7 @@ enum AnimationSoundType {
     AnimationSoundTypeLightRail,
     AnimationSoundTypePiston,
     AnimationSoundTypeArm,
+    AnimationSoundTypeStairs
 };
 
 struct AnimationInfo {
diff --git a/src/scene/scene_animator.c b/src/scene/scene_animator.c
index dde3c6c6..dace0270 100644
--- a/src/scene/scene_animator.c
+++ b/src/scene/scene_animator.c
@@ -20,6 +20,7 @@ struct AnimatedAudioInfo gAnimatedAudioInfo[] = {
     {.startSoundId = SOUND_ID_NONE, .loopSoundId = SOUNDS_BEAM_PLATFORM_LOOP1, .endSoundId = SOUND_ID_NONE, .pitch = 0.5f},
     {.startSoundId = SOUNDS_DOORMOVE1, .loopSoundId = SOUND_ID_NONE, .endSoundId = SOUND_ID_NONE, .pitch = 0.4f},
     {.startSoundId = SOUNDS_TANK_TURRET_START1, .loopSoundId = SOUNDS_TANK_TURRET_LOOP1, .endSoundId = SOUNDS_ELEVATOR_STOP1, .pitch = 0.5f},
+    {.startSoundId = SOUNDS_APC_START_LOOP3, .loopSoundId = SOUNDS_DOOR_METAL_MEDIUM_OPEN1, .endSoundId = SOUNDS_APC_SHUTDOWN, .pitch = 0.5f},
 };
 
 void sceneAnimatorInit(struct SceneAnimator* sceneAnimator, struct AnimationInfo* animationInfo, int animatorCount) {
diff --git a/tools/export_fbx.py b/tools/export_fbx.py
index d8cf32d9..8ee92ea0 100644
--- a/tools/export_fbx.py
+++ b/tools/export_fbx.py
@@ -4,4 +4,4 @@
 print("Blender export scene in FBX Format in file "+sys.argv[-1])
 
 # Doc can be found here: https://docs.blender.org/api/current/bpy.ops.export_scene.html
-bpy.ops.export_scene.fbx(filepath=sys.argv[-1])
\ No newline at end of file
+bpy.ops.export_scene.fbx(filepath=sys.argv[-1], add_leaf_bones=False)
\ No newline at end of file