diff --git a/shell/mount.sh b/shell/mount.sh
index 118f8e9..ed78546 100644
--- a/shell/mount.sh
+++ b/shell/mount.sh
@@ -1,52 +1,75 @@
 mo() {
 	local root="${1}"
 	if [ -z "${root}" ]; then
-		log_error "No root"
+		log_error "No root target directory"
 		return 1
 	fi
 	root="$(realpath "${root}")"
 	if ! mkdir "overlay"; then
-		log_error "Unable to make mount directory"
+		log_error "Unable to make overlay directory"
 		return 2
 	fi
-	{
+	(
 		if ! cd "overlay"; then
-			log_error "Unable to move into mount directory"
+			log_error "Unable to move into overlay directory"
 			return 3
 		fi
 		local directory
 		for directory in "lower" "upper" "work" "mount"; do
 			if ! mkdir --parents "${directory}"; then
-				log_error "Unable to move into: ${directory}"
+				log_error "Unable to make directory: ${directory}"
 				return 4
 			fi
 		done
 		local file="${root}/filesystem.squashfs"
 		if ! mount "${file}" "lower"; then
-			log_error "Unable to mount: ${file}"
+			log_error "Unable to lower mount: ${file}"
 			return 5
 		fi
 		if ! mount \
 			-o "lowerdir=lower,upperdir=upper,workdir=work" \
 			-t "overlay" \
 			"overlay" "mount"; then
-			log_error "Unable to mount: ${file}"
+			log_error "Unable to overlay mount"
 			return 6
 		fi
-	}
+	)
 }
 
 uo() {
-	cd "overlay"
-	if umount "mount"; then
-		rmdir "mount"
-		rm --recursive "upper" "work"
-		if umount "lower"; then
-			rmdir "lower"
+	(
+		if ! cd "overlay"; then
+			log_error "Unable to move into overlay directory"
+			return 1
 		fi
+		if ! umount "mount"; then
+			log_error "Unable to unmount mount directory"
+			return 2
+		fi
+		if ! rmdir "mount"; then
+			log_error "Unable to remove mount directory"
+			return 3
+		fi
+		local directory
+		for directory in "upper" "work"; do
+			if ! rm --force --recursive "${directory}"; then
+				log_error "Unable to remove directory: ${directory}"
+				return 4
+			fi
+		done
+		if ! umount "lower"; then
+			log_error "Unable to unmount lower directory"
+			return 5
+		fi
+		if ! rmdir "lower"; then
+			log_error "Unable to remove lower directory"
+			return 6
+		fi
+	)
+	if ! rmdir "overlay"; then
+		log_error "Unable to remove overlay directory"
+		return 7
 	fi
-	cd ..
-	rmdir "overlay"
 }
 
 mr() {