diff --git a/code/__DEFINES/rust.dm b/code/__DEFINES/rust.dm
index 6ac60f4de08..a78d48c341f 100644
--- a/code/__DEFINES/rust.dm
+++ b/code/__DEFINES/rust.dm
@@ -57,6 +57,8 @@
 /proc/byondapi_stack_trace(err)
 	CRASH(err)
 
+// MARK: MILLA
+
 /proc/milla_init_z(z)
 	return RUSTLIB_CALL(milla_initialize, z)
 
@@ -116,6 +118,11 @@
 /proc/create_environment(oxygen, carbon_dioxide, nitrogen, toxins, sleeping_agent, agent_b, temperature)
 	return RUSTLIB_CALL(milla_create_environment, oxygen, carbon_dioxide, nitrogen, toxins, sleeping_agent, agent_b, temperature)
 
+/proc/set_zlevel_freeze(z, bool_frozen)
+	return RUSTLIB_CALL(milla_set_zlevel_frozen, z, bool_frozen)
+
+// MARK: MapManip
+
 /proc/mapmanip_read_dmm(mapname)
 	return RUSTLIB_CALL(mapmanip_read_dmm_file, mapname)
 
diff --git a/code/datums/helper_datums/map_template.dm b/code/datums/helper_datums/map_template.dm
index 08437daa609..5858f9b1621 100644
--- a/code/datums/helper_datums/map_template.dm
+++ b/code/datums/helper_datums/map_template.dm
@@ -51,6 +51,9 @@
 	// if given a multi-z template
 	// it might need to be adapted for that when that time comes
 	GLOB.space_manager.add_dirt(placement.z)
+	var/datum/milla_safe/freeze_z_level/milla_freeze = new()
+	milla_freeze.invoke_async(T.z)
+	UNTIL(milla_freeze.done)
 	try
 		var/list/bounds = GLOB.maploader.load_map(get_file(), min_x, min_y, placement.z, shouldCropMap = TRUE)
 		if(!bounds)
diff --git a/code/modules/awaymissions/zlevel_helpers.dm b/code/modules/awaymissions/zlevel_helpers.dm
index 749abdf47a5..ca3cc60c150 100644
--- a/code/modules/awaymissions/zlevel_helpers.dm
+++ b/code/modules/awaymissions/zlevel_helpers.dm
@@ -13,6 +13,8 @@
 	 * turf in the world */
 	if(SSair && SSair.initialized)
 		SSair.setup_turfs(bot_left, top_right)
+	log_debug("Unfreezing atmos.")
+	set_zlevel_freeze(bot_left.z, FALSE)
 	log_debug("\tTook [stop_watch(subtimer)]s")
 
 	subtimer = start_watch()
@@ -39,3 +41,12 @@
 		for(var/otherthing in T)
 			qdel(otherthing)
 		T.ChangeTurf(T.baseturf)
+
+/datum/milla_safe/freeze_z_level
+	var/done = FALSE
+
+// Ensures that atmos is frozen before loading
+/datum/milla_safe/freeze_z_level/on_run(z)
+	log_debug("Freezing atmos.")
+	set_zlevel_freeze(z, TRUE)
+	done = TRUE
diff --git a/rust/src/milla/api.rs b/rust/src/milla/api.rs
index 8239cfc1d95..a92b648732e 100644
--- a/rust/src/milla/api.rs
+++ b/rust/src/milla/api.rs
@@ -703,6 +703,27 @@ fn milla_get_tick_time() -> eyre::Result<ByondValue> {
     ))
 }
 
+/// BYOND API for freezing a specific z-level.
+#[byondapi::bind]
+fn milla_set_zlevel_frozen(
+    byond_z: ByondValue,
+    byond_frozen: ByondValue,
+) -> eyre::Result<ByondValue> {
+    let z = f32::try_from(byond_z)? as i32 - 1;
+    let frozen = bool::try_from(byond_frozen)?;
+    let buffers = BUFFERS.get().ok_or(eyre!("BUFFERS not initialized."))?;
+    let active = buffers.get_active().read().unwrap();
+    let maybe_z_level = active.0[z as usize].try_write();
+    if maybe_z_level.is_err() {
+        return Err(eyre!(
+            "Tried to freeze or unfreeze during asynchronous, read-only atmos. Use a /datum/milla_safe/..."
+        ));
+    }
+    let mut z_level = maybe_z_level.unwrap();
+    z_level.frozen = frozen;
+    Ok(ByondValue::null())
+}
+
 // Yay, tests!
 #[cfg(test)]
 mod tests {
diff --git a/rust/src/milla/constants.rs b/rust/src/milla/constants.rs
index 550ec73fcc1..75ba648af5d 100644
--- a/rust/src/milla/constants.rs
+++ b/rust/src/milla/constants.rs
@@ -1,5 +1,5 @@
 /// How many Z levels we allow before being suspicious that the wrong number was sent.
-pub(crate) const MAX_Z_LEVELS: i32 = 10;
+pub(crate) const MAX_Z_LEVELS: i32 = 15;
 
 /// How big is the map? Assumed square.
 pub(crate) const MAP_SIZE: usize = 255;
diff --git a/rust/src/milla/model.rs b/rust/src/milla/model.rs
index 4b7ac10036e..838bb090cce 100644
--- a/rust/src/milla/model.rs
+++ b/rust/src/milla/model.rs
@@ -401,6 +401,7 @@ impl From<&InterestingTile> for Vec<ByondValue> {
 pub(crate) struct ZLevel {
     tiles: Box<[Tile; MAP_SIZE * MAP_SIZE]>,
     pub(crate) active_pressure_chunks: HashSet<(u8, u8)>,
+    pub(crate) frozen: bool,
 }
 
 impl ZLevel {
@@ -412,6 +413,7 @@ impl ZLevel {
         ZLevel {
             tiles: unbuilt.into_boxed_slice().try_into().unwrap(),
             active_pressure_chunks: HashSet::new(),
+			frozen: false,
         }
     }
 
@@ -455,6 +457,7 @@ impl ZLevel {
             self.tiles[i].copy_from(&other.tiles[i]);
         }
         self.active_pressure_chunks = other.active_pressure_chunks.clone();
+		self.frozen = other.frozen;
     }
 }
 
diff --git a/rust/src/milla/tick.rs b/rust/src/milla/tick.rs
index ee197e5788f..ca0f126beae 100644
--- a/rust/src/milla/tick.rs
+++ b/rust/src/milla/tick.rs
@@ -95,12 +95,14 @@ pub(crate) fn tick_z_level(
     // Initialize the new frame as a copy of the old one.
     next.copy_from(&prev);
 
-    simulate::find_walls(&mut next);
-    simulate::update_wind(&prev, &mut next);
-    simulate::flow_air(&prev, &mut next)?;
-    simulate::post_process(&prev, &mut next, &environments, new_interesting_tiles, z)?;
+    if !prev.frozen {
+        simulate::find_walls(&mut next);
+        simulate::update_wind(&prev, &mut next);
+        simulate::flow_air(&prev, &mut next)?;
+        simulate::post_process(&prev, &mut next, &environments, new_interesting_tiles, z)?;
 
-    next.active_pressure_chunks.clear();
+        next.active_pressure_chunks.clear();
+    }
 
     Ok(())
 }
diff --git a/rustlibs.dll b/rustlibs.dll
index 9ff2cf0ca90..7d375e48185 100644
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diff --git a/rustlibs_prod.dll b/rustlibs_prod.dll
index fde6bd0f899..9cecefa4bec 100644
Binary files a/rustlibs_prod.dll and b/rustlibs_prod.dll differ
diff --git a/tools/ci/librustlibs_ci.so b/tools/ci/librustlibs_ci.so
index 96e744b5efb..96da50944ae 100644
Binary files a/tools/ci/librustlibs_ci.so and b/tools/ci/librustlibs_ci.so differ