I think JB would be a little flustered when you walk in on him, but would quickly recover after walk out muttering 'sorry'
I think Mark would be flustered, but would laugh it off as soon as you walked out of the room.
Jackson wouldn't be shy at all, because he's really proud of his body and likes to show off. I feel like he'd ask you if you would like to join him in getting naked.
Like JB, I feel like Jinyoung would be a little flustered at first but then go back to his normal self after the incident.
I feel like our little fluff would be so embarrassed his entire face would burn redder than a tomato.
I feel like Bambam would be really confused at first but realize what happened after you walk out.
Yugyeom would be a little like JB and a little like Jackson. I feel like he'd get all shy and then turn into a cocky mess asking if you liked what you saw.