Eisuke: You were surprised to learn that the great Eisuke was in fact horrible at singing. When you heard him singing to himself in his office you thought it was a cat or some kind of creature being murdered. You cringed in disbelief. Always acting like he was good at everything you thought you could use this to your advantage in the future and decided to keep it a secret you overheard him until the day you would spring it on him and get your oh so sweet revenge for when he teases you. Of course you recorded his session on your phone so you can play it back to him.
Soryu: You thought you would go see Soryu at the Ice Dragons HQ when you heard what sounded like singing coming from his office. Putting your ear against the door you listened carefully and you recognized the voice was definitely Soryu's. You began to giggle to yourself as you listened in. He sounded so adorable, in fact his singing wasn't half bad but imagining a mob boss singing to himself was not how you would picture someone people are meant to fear.
Ota: Deciding to go out to Karaoke because you thought it would be fun but you soon regretted it when you heard how atrocious Ota's singing was. You didn't know he was completely tone deaf and if you did you never would have mentioned on going out that night. It made your ears bleed and you wished you could run away and hide. Even worse, Ota didn't want to stop, and you didn't have the heart to tell him how horrible he really was and so you put up with his ear splitting singing all night long.
Baba: Hearing something coming from the penthouse lounge you decided to investigate and were shocked to find Baba alone in the room singing to himself while dancing. You didn't think this was how Baba spent his free time. And to your surprise he was actually pretty good. It was like your own private show he was putting on and you had front row seats.