You also have to remember that whatever you choose to have as your emergency tool(s), they need to be accessible after the crash, as well as before when you are fat, dumb, & happy. You could very well roll several times, be crashed into from behind, or any number of scenarios.
If you simply place the tool in your door pocket in hopes to use it after a crash, you may be sadly mistaken. It may wind up in the back of the vehicle, or even thrown from the vehicle. You need to figure a good way to secure it, so it will be within reach, and will not be a projectile to injure or kill you or your passengers.
These are good questions, but let me give you some answers based on my experience as a firefighter.In the time it takes to find a tool and cut the seatbelt, couldn't you just unbuckle the seatbelt? I'm having a hard time imagining a crash such that you wouldn't be able to unbuckle the seatbelt.
And if you are in crash that damages the door badly enough to get it stuck, wouldn't the glass explode anyway? IIHS does tests with the side windows down for some reason (maybe they got tired of cleaning up broken glass!), but if you watch the 4runner small overlap test you can see the side glass explode inside the door on the slow motion shot.
These are good questions, but let me give you some answers based on my experience as a firefighter.
Sometimes after a crash it can be very difficult to unbuckle the seatbelt. The buckle can be under considerable tension after the belt pre-tensioners activate and this makes pressing the button quite hard. Also, it can often be impossible to physically reach the buckle after interior parts move around. But in most cases, a user will be using a blade to cut a belt on someone else, not themselves. From the outside reaching in to unbuckle is vary hard, it's much easier and faster to cut the belt closer to the doors.
Todays autoglass is very strong and remarkably flexible. You would be surprised to see what it can survive without breaking. I've needed to break the glass on stuck and buckled doors dozens of times.
Lol I have a lot I can use but the first thing in mind is my hatchet I have next to my driver seat..