Second Conditional Sentence

Hello,

According to the second conditional (englishtest.net/lessons/13/index.html), the tense in the subordinate clause is past simple and the tense in the main clause usually uses the auxiliary would with a simple conjugation. However, in this sentence, the subordinate clause is in the second conditional, but the main clause is without any auxiliary would. Therefore, I am baffled by this case. Could you please clarify why the main clause is in the present tense “Please do not leave school with your parent” rather than “You would not leave school with your parent”?

Here is the sentence I heard from the TOEIC listening part IV, set 7, exercise 6:

Please do not leave school with your parent unless you were signed out at the office.

english-test.net/toeic/liste … grams.html

Thank you.

Best wishes,
Bhikkhu1991a.

It looks strange to me, I would say
“Please do not leave school with your parent until you have been signed out at the office.” (could also be unless you have been signed out I suppose)

-to put it another way - if you haven’t been signed out at the office, please don’t leave school.

…but that’s just me, and I didn’t bother doing the listening test so I may be out of context.
I guess it is a mixed conditional, but not necessarily the clearest of examples.