Your star witness has already admitted that the wall was inadequate:
_________________________________________
Zoo Director Says Tiger Wall Was Low
SAN FRANCISCO (AP) - The director of the zoo where a teenager was killed by an escaped tiger acknowledged Thursday that the wall around the animal’s pen was just 12 1/2 feet high - well below the height recommended by the accrediting agency for the nation’s zoos.
http://www.freerepublic.com/focus/f-chat/1945139/posts
I don't consider the zoo director a witness. I said the wall was adequate for 67 years. I also said before that I considered the wall was too low to guarantee the tiger wouldn't get out. The fact that it took the tormenting with slingshots to get that tiger to jump out of that pit means the pit depth was adequate and the zoo's treatment of the animals had been good all along.