So I'm finally playing in my first Dresden Files game (which is awesome by the way).  My character is a Scion of a djinn and a mortal, and one of the things that seemed very fitting for the character was supernatural toughness, with the catch being true magic (based on the mythology that the djinn cannot be hurt by normal weapons and must be fought or trapped with magic).  Until recently it worked out fine.  Where we ran into an issue was when I fought my first magic user.

The DM and I were both having trouble wrapping our heads around how the catch interacts with the extra 4 boxes of physical stress capacity that supernatural toughness grants.

So my character normally has 3 boxes of physical stress capacity from his endurance, plus 4 more from supernatural toughness for a total of 7.  But if I get hit by magic I only have 3.  That's where we were getting confused.  So what happens if, for example, I get shot and take 3 boxes of physical stress, then get hit with a bolt of lightning for 3 more?  Am I taken out or not?  The 3 stress from the lightning would fill my 4th stress box (which isn't there when my catch is satisfied), but the physical damage I took first could fill the 4th box with no problems.

And does it matter which order I take the damage in?  If it was switched and I took the lightning bolt first and then got shot would it result in a different outcome?