Step 1. Die overheats.
Step 2. Die melts, becomes 3-way short. Gate oxide is disturbed, junctions are melted together.
Step 3. Fault current ensues. Melt spot becomes vaporization spot; die surface and bondwires evaporate into plasma.
Step 4. Supersonic plasma ball builds pressure until the package is fractured, releasing a sharp "CRACK" into the surrounding air.
It would seem your example went through at least steps 1-3, and had little gate current to vaporize that bondwire, leaving a 2-way short.
Drain will almost never become open, because it's the tab the die backside is glued onto. source bondwires will vaporize instead. Gate may become disconnected due to the cracked package if step 4 is reached, or remain connected after all.
Note that during steps 3 and 4, the transistor becomes an all-way short, exposing gate and source circuits to some fraction of drain circuit voltage. This can destroy e.g. gate drivers, even behind a coupling transformer, even if the device ends up a three-way open. Transients are not to be underestimated!
I've seen a lot of "silent" deaths in my work. Steps 1-3 are followed, but there isn't enough energy available (or the device doesn't fail in a low enough resistance mode) to blow open the resulting short. A bit annoying for fault finding, but, it doesn't leave shrapnel which is nice, right?
Tim