I recently had the same unfortunate experience at Rawal Lake. My Pajero TD was also stuck due my mistake, I ventured too close to the water. Lucky for me, a group of gentlemen in their Defender helped with the towing, shovelling the mud, etc. And amazingly many other people helped pushing the Pajero out, but it was stuck.
I am grateful to everyone who helped with the efforts.
In the end after about 2 hours of struggle, the Pajero was pulled out by a bulldozer, (which was there pulling out a Daihatsu Rocky.)
On a final note, just be careful while cruising the dry lake, it is soft in some places, and before long you will find yourself stuck in the mud.