Question 10 - AnswerThis one is a classic that's popped up a few times on this board. In fact I got the idea for this question when I looked through some very old posts and saw Trashman having almost the exact same problem.
The answer is that at the start of the mission the Fenris isn't destroyed so that part of the SEXP comes true instantly. Using And instead of And-in-sequence is the correct answer here.
And-in-sequence is a powerful SEXP but most people have made mistakes like the above and become wary of using it. But that's one more reason I said it's good to get rid of superstition. Better to know why your attempt to use and-in-sequence didn't work than to avoid using the "cursed" SEXP.
Question 11 - AnswerI was a little nasty with this one as it's actually two questions in one. Quite a few got it correct as to why the use of in-sequence wasn't working but less people understood why random-of hadn't worked and thought it was the same issue.
The in-sequence SEXP won't move onto the next argument in the list until the one it is currently dealing with has been invalidated. Since this wasn't happening the event would keep repairing turret01 forever. What you need is something like this

Unfortunately that crashes almost any build of FS2_Open since they don't have the fix I added to SVN last night (It's in
this build). But since there is a more complicated way to make that work with even 3.6.9 (using variables to pass the argument to the inner when) I considered it a fair question.
As for using Random-of I'll give everyone an extra day to go back and see if they can figure out what's wrong there.