Maybe they simply sent #0x3CA2 to the client when you enter the instance.
So far you can get it with the following maps:
ID WorldCodeName128
40 INS_ROC_TOP
19 INS_QNO_TQ_BAEKRYEONG_10
20 INS_QNO_TQ_BAEKRYEONG_13
21 INS_QNO_TQ_BAEKRYEONG_14
22 INS_QNO_TQ_BAEKRYEONG_15
23 INS_QNO_TQ_BAEKRYEONG_16_1 or 2?
Zerk Quest instances
I tested INS_QNO_TQ_BAEKRYEONG_13, because you can simply give yourself the quest and open it multiple times, if you abort the quest. With #0x3CA2 i've got the following stuff:
If you add something to your "filter" like "if teleported to map XYZ, send #0x3CA2" it might work without trigger too. Just make sure there is nothing else going on, like mobs during this time.
You could do your own scripts if you analyze the script files in "q_script" directory.