They do have a past together, when Jin finished talking with the chairwoman and was on his car saying that he was sexually frustrated and stressed, he got some missed calls from Brandon, and when Jin called him back, Brandon said to him "You know you can call me if it isn't enough for you, you know doing it from the front and you need something from behind'
Yeah ik that part oops i guess i worded it wrongly, i meant to say im looking forward to the flashbacks of jin and brandon before he betrayed shinhae, the past as in romantically(?) bc before jin beat up that blonde bastard he was spewing shit that jin had slept w brandon and was obssessed with him for a while

This Brandon has the same eye color as Jin's chairwoman