The zoo staff had a split second to make a decision and they made the right one. Jack Hannah was on several morning shows and backed them up. He has a house about 3 miles from where the gorilla came from and said the animal was showing indications of elevated alarm. The pain from being darted would have had a high probability of setting him off and would have taken 5 or 10 minutes to affect him because they’re administered intra-muscularly. Even administered intravenously a dose high enough to stop him instantly would have likely killed him. I just hope it was a big bullet to the brain so he never knew what hit him. And it was a male gorilla.
I’m not buying there were no options. Just the time it took to get the gun and make the shot meant they had other options. Then of course there’s the fact that sometimes shots miss, if they’d just wounded the gorilla you wind up in the boat people are claiming a tranq would have put them in. Sorry, they had a choice, they chose poorly.