I don't think they're immune but they probably know what happens. So I think if a draconian is looking like he's in trouble, his colleagues might start to move away from him to reduce their own vulnerability - or even use the death throes to their advantage.
This is the thing I noticed that has changed since the original version, whose petrification trapped the weapon they were killed with, and ergo did not affect allies. But I won't be using Baaz, since this is a very high level adventure, so they will go down quickly enough even with the tougher draconians. So their death throws ability is the only one that's likely to trouble the party. I will assume the draconians know and adopt a loose formation as much as possible.
That's how I would run it too. Draconians are short-term point-and-shoot living weapons designed with nothing more than killing in mind. Their survival isn't really a factor that influenced anyone's thinking. They're the unstable and disastrous consequences of magical tampering, and Takhisis probably has a laugh any time one dies because, at the end of the day, that's a metallic dragon that never got the chance to be.
The draconians in Fizban (non-Krynn) are listed as any alignment, and it adds recipes for making them from chromatic and gem dragon eggs.Kind of wish 5e had kept the Noble Draconians from 3e's Revised Krynn Bestiary instead of just making the Chromatic Draconians another group of evil Draconians. Then your good Draconian character could be the one to make the noble sacrifice for his teammates.
