LOL!
I don't think it's so much the sex, as it is the sheer blasphemy of it all. I mean, this is right up in G-d's face.
The guy was 38, and he has a heart attack. There is very little chance that this was not a direct Act of G-d.
Note to the rest of you: Don't have sex against the West Wall on the Temple Mount, either. It's the same G-d and he'll do ya for that too.