Thank you so much for that explanation; it was very enlightening. The truth is I'm actually doing this as part of a maths poster in order to show probability in an interesting way (a poster that says ' what's the chances of me appearing on the other side of a wall?' in bold lettering attracts...
Apparently, if all your particles are primed for tunnelling through a wall then you can walk through it, but the probability of all your particles tunnelling simultaneously is so low that you would have to attempt it more times than the age of the universe in years. Could someone please explain...