My parents were living in dorm housing during the events and participated in the student protests. They've told me they had a bunch of exchange students from Africa, other European countries and pertaining to this question North Korea and all lived in the same dorm. During said events the Koreans seemed to disappear overnight as they've told me and I'm wondering what happened. Were they sent to reeducation camps or just continued their education in Korea or maybe disposed of after having been exposed to these events?
Officially, obviously nothing.
At the time, media close to Seoul reported that they were sent to a 2-month reeducation camp course and were to be limited in their job postings to only rural areas. I believe this to be generally correct.
North Korea only arrived gradually at the decision to withdraw their students from all of Eastern Europe. When they did, they took swift action, with the occasional random show of leniency. For example, in Hungary, students were collected dramatically fast. In the case of the students in the town of Szeged had only 3 hours to pack up after the embassy officials showed up in a van; even their academic record books were left with the university. However, (although only initially) a few engineering students at BME who needed a bit of extra time to finish their studies were granted a (later rescinded) reprieve from returning home.
As to their ultimate fate, whether or not the state had a change of heart in whichever direction, to my knowledge there's no information. But for context one should consider the following:
At least some students believed that their options were to be sent to a camp or to be disappeared, so there's that.
But there's at least one close precedent that we can look at: after the 1956 revolution in Budapest, North Korean students, like in 1989, were ordered back to their home country. At that time, they were allowed to continue their studies in Pyongyang.
That solution, although obviously nicer than the other options, was still less than ideal for the students. They received no assistance in switching their professional dictionaries from Hungarian to Korean, and generally afforded few thoughts of special care: a least one poor guy had to forget about diploma altogether, as his Hungarian course (textile design) didn't have any comparable alternatives in North Korea.
However, if the case of the 1956 students did indeed inform the decisions of the North Korea party officials, then it most probably was a strong argument for choosing reeducation camps. Back then, at least one North Korean professor complained that the repatriated students pose 'incorrect' questions and continue to denounce the prevailing, Soviet-backed Hungarian government.
Reports also took note of graffiti and flyers lauding the Budapest revolution appearing between the walls of Kim Il-sung University.