very sad, but i agree with mousekilla. If one of our animals escape it is our own fault, and we know it. if one of us gets bit handling a venomous animal, we all know we are responsible, because we accepted that risk. A zoo is not different.
Double J, you brought up a lot of good points, but the problem with "ifs" is they are just that, "ifs" and not "were". Tranquillizers were not immediately on hand, or used in time, or people didn't know how to use them. A thorough audit does need to be done, but that doesn't fix what happend due to human negligence. As far as the gorilla just showing agression, or bluffing, i really don't think grabbing a kid in its mouth qualifies as "bluffing".
And for the "20 foot" thing, if anything the officers waited too long. I'm told Canada has pretty strict gun laws, but if you've ever had law enforcement or concealed weapons training you will learn the "21 foot rule". basically it shows that a human being, armed only with a knife, can close 21 feet and deliver a wound before an armed person can draw their weapon and fire. I don't know what the gorilla/human rate of speed is, but if i was that officer i would not have waited around to figure it out.
ignorance can be cured, but stupidity is forever