If you’re accurate a .22 is plenty to kill one of these monsters.
If being chased up a tree by a monster crocodile or alligator isn't enough of a reason to use heavy weapons, I don't know what is. Twenty-two? Eh. I'd want the satisfaction of blowing him up good. And even after it was raining reptile meat, I still wouldn't come down from the tree for two days, just to make sure.
Lord, what a nightmare. Thanks for reminding me why I don't want to live in Florida.