If your are second internally, you will get the 2nd highest external mark from your cohort as you internal mark.
So if your cohort is pretty decent, 2nd and 3rd should be fine.
NO
The only two exam marks that are used are the top and bottom - to determine the range of marks for the cohort.
After that they take into account the total marks earned in the exam - as that sets, within a mark or two, the total marks available for the cohort's assessment marks. They also use the same median and mean. After that the relative gaps come into play.
It is NOT a simple matter of second exam mark goes to second ranked student internally. That could be grossly unfair. If there is one mark between two students sent in by the school they will keep that one mark or maybe extend it to two or three if necessary.
There are, of course, times where the second ranked person will get the second exam mark but that is because that is the marked determined by the above process not because it was the second mark.