Currently the script tries to create a directory for the mount point in the current working directory (which may or may not be writable, depending on how the user runs the script) and it uses a hardcoded name (temporary_raspbian_mount_point).

mktemp -d can be used to safely create a directory that is guaranteed to not exist before and (by default) is created in the system's default temporary directory for the user who runs the script (but this can be changed if needed).

If you need to create the mount point in the current working directory then you can still use something like MOUNT_POINT=$(mktemp -d temporary_raspbian_mount_point.XXXXXX) where mktemp will change XXXXXX to a random string to avoid clashes and race conditions. It will also create the directory so mkdir will not be needed.

Script should be using rmdir that deletes an empty directory only.

It should prevent emptying the image if it is not unmounted properly.