If you were in a car that went off a bridge and had to cut your seatbelt, would you use a key?

I mainly use mine to cut things, like one time my shoe lace somehow tied itself around my pedal spindle, and I couldn't move my foot to untangle it, so instead of taking my shoe off in the rain I cut it and went on my way.

The most useful time for me is cutting zipties which I have to do frequently.

Edit: If the knife I carried wasnt so thin, light, and cool, I would probably not always have it in my pocket, but i barely notice its there.