It is expected than picks of Mohs Hardness Scale of 7 and above scratched with some pressure will leave from marks to deep dents into a Gorilla Glass screen.
As soon as does that, he compromises the structure of the complete glass by going through the coating and attacking what makes up the material's compression stress.
This is why it is not surprising to see it shatter. It doesn't mean that the glass is particularly fragile. Any similar glass construction will behave about the same once the damage goes past the coating.
I don't get the point of the lighter burn test. Maybe because I don't smoke?
The bend test however isn't looking too great.
At least it seems to bend above the battery so that one should be reasonably safe.
Edit: I agree the bend test might not be representative however due to the prior shattering of the display, then unable to participate to the structural rigidity.
See https://d3nevzfk7ii3be.cloudfront.net/igi/ZlpUoq3OjhHJsqTo.huge: it bends right in between the battery and board areas.
Now let's see how other phones behave when subjected to the same treatment by the same person for comparison!