2 entries M-visa query

I have obtained a 2 entries M-type for 30days each stay duration. I have entered China using my 1st entry.
I am nearing the end of my 1st entry 30days. And I was wondering what is the easiest(cheapest) way to re-enter China on my 2nd entry M-type.
Can I buy a cheap one way air-ticket to Hongkong(anywhere), clear the China International airport custom. Stay in the transit area without getting onto the plane.
After half and hour, then I join the incoming passenger queue at the custom to 'return' to china utilising my 2nd entry M-type.

Is this allowed? I dont want to get into trouble with the law.
Thanks.