Hopefully I am not mistaken, but if both you and the student ranked first manage to score a perfect mark in your Latin Extension HSC exam, then you should both also receive 50/50 as your Assessment Mark, resulting in a perfect HSC mark for both of you, in which case both of you should state rank this subject.
Recalling the moderation process, the highest Assessment Mark (i.e. that of the student ranked first) is adjusted to equal the highest Examination Mark of any student in the cohort. For example, if you or the other student achieves an HSC exam mark of 48/50, which happens to be the highest, this mark will also become the Assessment Mark (internal mark) of the student ranked first. Similarly, the lowest Assessment Mark (in that case, your mark, since you are ranked second out of two students, which is technically last) is adjusted to equal the lowest Examination Mark of any student in the cohort. For example, if you or the other student achieves an HSC exam mark of 43/50, which happens to be the lowest, this mark will also become your Assessment Mark. I believe that this process would also apply to a cohort of 2 students.
I hope this helps!