I was kinda thinking the same, because it feels like the tempo slows down but then bam the singing starts "right away" for me.
When you say fast, do you mean it goes by too fast, as in, the chorus is too short, or do you actually mean fast as in it seems like the tempo is faster than the rest of the song? If the former, then I agree, it definitely is shorter than other choruses, but I wouldn't really go as to say it's too short to the point where I'd think there should be more to it. If it's the latter, then I don't think it's going at faster tempo.
NOTE: Please take any Japanese translations/interpretations from me with a grain of salt. I am no where near proficient. I usually just understand words or phrases then guess what they're talking about. Thank you!