What would you do if you were trapped in your car after and accident or submerged in water?  Would you be able to cut your seatbelt into or break you glass if needed?

Check out his video where Mythbusters tests the theory of opening a car door under water.

[youtube]http://www.youtube.com/watch?v=2YaMEW30bv4[/youtube]

Hopefully, you will never be in this circumstance, but there is a tool that you may want to keep handy in your glovebox or center console if this should happen.  Click Here