" It ended up being tangled with the main gear and the fire crews having to cut it free "
Did it indeed ?. The 737 tow bar is hardly a small piece of kit and, if correct, would suggest it was clearly disconnected and ready to be re-connected to the other large bit of kit, the tug..which is clearly visible ( usually) from the flight deck. Given the distance from the nose to the main gear, how it ended up embedded in the latter to the extent it had to be cut free ( as stated here ) is "interesting" to say the least.
More questions than answers ( as always ) and the official report will no doubt make equally interesting reading as should the human factors aspect.