So I left the biggest cell
Perhaps not entirely the best move. A bit of thought necessary and we don't know all the useful facts.
Capped queen cells? If so, JBM is likely correct.
Any eggs? If so you will need to go back in after day 6 to break down any more produced. If you know the age of any eggs, of course.
Was the retained cell capped? If so, you won't know when it will emerge (or even if!), so going back in before emergence is a bit of a lottery.
How simple to break down capped cells, select your chosen cell, mark the frame and go back in in a week? Open cell now - so you know it is viable. They are not so likely to build any more if several are left now, in a week you may well see that the selected cell is ripe, so can remove the rest in one go.
Your other capped(?) cell chosen for the Q- colony could be checked for emergence or ripeness before destroying these cells. You would be up the creek without a paddle, particularly if both cells failed, and they do not make more cells. But possibly scrubby and small cells which may not be so easy to find.
Leaving or moving recently capped cells is not the best way of doing things, either.
Unless you tell us all the details, others might not get the complete message. Maybe you did leave an open cell, but all the learners reading this will not pick up on all the salient facts.