Transfer root to SDcard with switch_root didn't work

I'm trying to install Debian on the Android 4.4 (modded with cyanogenmod) that's installed on my nexus 10 to one external sd card. I'm reading this tutorial :

http://ift.tt/1iiwWx8

I've attached the Leef microSD microUSB Connector with a 64GB sd card inside to the mini usb port of my nexus 10 as you can see here :

The tutorial talks about the The ASUS Transformer TF101 and the instructions are based on this tablet. Instead I have a tablet nexus 10,that's equipped with an internal sd card where I have installed android 4.4 + cyanogenmod. For this reason I need to know how to change some part of the tutorial to adapt it to my situation. Anyway on my desktop computer I have partitioned the sd card in this way :

Disk /dev/sdf: 64.0 GB, 64021856256 bytes
255 heads, 63 sectors/track, 7783 cylinders, total 125042688 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0004504c

   Device Boot      Start         End      Blocks   Id  System
/dev/sdf1            2048    32767999    16382976    b  W95 FAT32
/dev/sdf2        32768000   125042687    46137344   83  Linux

My nexus 10 recognizes the sd card as sda2. I have mounted it giving the following commands :

mount -o rw,remount /
mkdir /mnt/deb
mount -t ext4 /dev/block/sda2 /mnt/deb

So,now the sd card is mounted on /mnt/deb. Let's go on the section of the tutorial where I'm freezed. It says that I have to transfer root to sdcard giving the following command :

exec /sbin/busybox switch_root /mnt/root /etc/init

Since my busybox is located inside the folder /system/xbin/ and I have mounted the sdcard into the folder /mnt/deb and I have the file init inside / and not in the folder /etc,I have changed the command above with this :

exec /system/xbin/busybox switch_root /mnt/deb /init,

but this is the error that I get :

but where is the mistake ? the tutorial says to mount the /proc and /sys filesystems,but they are already mounted on the / folder of my tablet if I don't go wrong,because the nexus 10 has an internal sd card and android is installed there. So,please can you help me ? thanks.