I think mla's question is the key to us being able to advise you. If you're like collegecpa and have had short study periods for other exams with success, then by all means go for it. If you're studying full-time, then for a single-week cram, you should be able to get in 60-70 hours of study (yeah, that's a long week, but for one week, you can put in the effort), and that's enough hours for BEC.
However, if you're like more of the people on here and doing 3 months for an exam on average, then to think that you should re-do your whole method and switch from 3 months to 1 week just to get in 1 score release, that's crazy.
Given you're even considering it, I'm guessing you're not a 3-months-per-exam person. But even if you've been doing a month per exam, 1 month cut down to 1 week is still an extreme change. I'd consider doing 2 or 3 weeks instead to not risk having to wait till October. However, my risk appetite is generally quite low. 🙂
If the BEC material is coming easily to you, then go for it. But be willing to reschedule at the last minute (I think 24 hrs in advance is the shortest re-schedule that's allowed, though at a large fee) if your scores aren't high enough. If you're scoring 50's on MCQ's 24 hours before, you're not likely to pass day-of, and better to re-schedule a week later than to be stuck waiting till October.