Uhhh... they were:
A strong warrior from the North.
I don't believe it is likely a strong warrior would survive such.
A powerful spell-casting mage.
To be honest, I found the powerful spell-casting mage more likely, yet I can see it easily fall in combat as well.
A sneaky lock-picking thief.
I believe that a sneaky lock-picking thief or the silent ninja assasin would have the most chance of surviving something like that.
A silent ninja assasin.
See previous answer. I picked the thief because I have less with the ninja thingy.
A summoner who can call up powerful beasts.
I don't see much of a difference between this and the "powerful mage", my odds still go to the thief and/or the ninja.
The glass is half-full.
No particular reason.
The glass is half-empty.
No particular reason.
The water's poisoned.
I trust people a bit more than to presume the water is poisoned.