Do I have to go through immigration to get a reentry permit at the airport?

Hey folks. Just a quick question.

I have a single trip reentry permit and I leave for Singapore this weekend. I arrive in bkk on the 1st and then leave for Taiwan on the 2nd. I'm on a non-b immigrant visa.

My question is, when I land at suvaranbhumi on the 1st in the morning, is it possible to just apply for my reentry permit there and then rather than rushing about getting it before my second flight? Or do I need to go through immigration to get the reentry permit at the airport? (meaning I would need to do it while going for my second flight)

I would do multiple reentry but my visa is renewed end of the month so it's not really worth it tbh.

Thank you in advance.