Calm - I'm extremely calm about 98% of the time. It's probably my most immediately noticeable trait, and it sometimes causes people to accuse me of not caring about anything.
Clever - Saying that I am would be shameful self-flattery, so I'll just say that most other ISTPs that I have known (only a few, oddly enough) are very clever. I am overly-jokey, though, if that's any kind of proof.
Always into something new or unusual - I go through multiple obsessional phases per year over random subjects.
Mentally impossible to break - I am suspicious of pretty much everyone and I'm never emotionally vulnerable (or, if I am, I control my behavior and I don't let anybody else know that.) Those two traits combined would probably make it pretty difficult for anyone to "break" me.
Weirdly easy going - Well, yeah. I don't know how weird that is, though.
Loves you with a level of intensity that you can't imagine - I guess? I don't know.
Protective - I didn't realize until recently that I did this sort of thing. But I guess I always have.
Go find a manual on how to diffuse a bomb - Is this referring to rage? If so, my rages are few and far between. I DO have them, though.