Cynic,
Great question.
That is one of the many reasons why my Large Seb get's more pocket time than any of my other folders.
It could easily be used as a Baton / Glass breaker etc, and what makes it best, is that it is extremely comfortable to hold in a closed position. I am a righty, and seems to fit my hand best when I hold it with the clip side down, and the blade spine touching the front of my hand.
Not sure if Mr. Reeve would ever admit it, but by the way the ends are made on the handles, I think a closed defensive/offensive application was in mind with the design.
As far as whether it would hold up if used that way, I have no doubt it would.
Just to add, I aggree with others on this, that I hope to God none of us ever have to find out how it / or any other object would work in a real Self Defence situation.