I have a fan question:are you aware that Japan in Japanese is not pronounced as Japan and that the word actually translates roughly into something like "kaboom"?
Actually, Japan in Japanese translates into Nippon or 日本. Where did you get the idea it turns into "kaboom"? Japan is the name used mostly by foreigners.
Those subtitles are clearly wrong. I've lived in Japan for 5 years and speak the language every day. I've never once heard any Japanese person say Kaboom.