Megan asked me to look at this thread, saying "It will settle the substrate argument once and for all". I don't know about that. Frankly, both Shamrock and Megan have had a huge amount of luck, in my opinion. How you managed to get the pebble out without causing internal damage to her is a minor miracle. I think there needs to be a large disclaimer on this thread for anyone thinking of trying to same approach, indicating that it is a dangerous, last resort.
So no, I don't think this settles the substrate argument once and for all. All it does is reinforce the point of using large pebbles (larger than this one obviously), sand, or no substrate. But we knew that already.