Yeah, i had been curious about Geng was forced to use a mask at SuJu's performance when they first debuted. I search for the video for a long time, but never find it. And suddenly, i re-watch strong hear eps.04 when Eunhyuk told his story, they put the clip of that performance, and i spotted geng there. with his mask. I felt like crying watch him danced with that mask... TT_TT

this is the link 'Strong Heart Full'

For them who was curious too, check for eps 5 at 64:14-64:18 the most left members (most right from our point of view).