Goblins IX: For that, you shall DIE!

[Imgran]

I'd say this is arguable. I mean he's a lizardfolk with no significant other attack methods to fall back on. Considering his bite does as much damage as a shortsword and his body is adapted to take SERIOUS damage he'd be at least entitled to a save, if only because at that point he has no real options.

He had an option -- leave the finger poking out of the hole in the glass the heck alone. And thus he deserves the consequences of failing to do that.

To metagame for a second, when you see a monster like that removes from you by exactly one destructable barrier, the correct reaction is to move on as quickly as possible, disturbing as little as possible. Because it's obvious there's a mistake you can make that will set the monster loose. SAure, the GM is going to look for a way to inflict that segregated monster on you anyuway, but that's no reason to make it easy.