I too thought that the 3-piece emergency door tool was a good investment.until it did not work for me.

The plane was parked outside at Reno when the wx got down close to freezing and when I tried to rotate the fwd door handle, it just rotated freely without unlatching.  Not sure why the tool didn't work as advertised, but it didn't.  Anyway, after I finally got the door open  (don't ask), the head of the setscrew had sheared off and needed to be replaced.  I agree that the screw size should be larger.  Perhaps with a group effort, we could persuade the factory to make a change????

I also carry the 1/2 " box/open-end wrench and the phillips screwdriver that Bob P. mentioned inside the plane  .  Everyone should.

Regards, Bill Hogarty