Just curious, have you ever seen a Glock field knife break at the tang? IME it's an extremely robust knife for its size and weight, which is not a lot more than a Mora and a good deal less than a USMC Kabar or many other 'sharpened prybars' in the 6-7" blade length. I have seen the Glock stand up to an awful lot of abuse, stuff that most of us would never be willing to try with a more expensive knife, including prying open a locked door and punching holes through sheet metal. While I'm not affiliated with the brand in any way, they do know how to make a near-indestructible product.
But anyway, that's totally beside the point. I'm not in any way advocating the idea of relying on the Glock field knife or any other fixed blade in general as your primary rescue tool. It's important to keep in mind though that for practical reasons, very few people keep a full-sized rescue tool in their car. A knife is a different story though, many of us have one within reach for all kinds of utility tasks. It's worthwile to consider that a robust knife, even if by no means ideal for the purpose, can be used as an emergency rescue tool if absolutely needed and in the absence of a better alternative.
99% of the time, such extreme measures are not needed and it's far better to let the pros handle the situation. However, if no help can be expected and push really comes to shove - what do you do? Give up altogether because you're not ideally prepared for the job? Or at least give it a honest try to do something about the situation with what you have at hand?