You did take the mirror out of the mirror cell before soaking it ...
... right?
Uh, sorry, just read your post properly. I don't think soaking the mirror cell and all is a very good idea. Now what's done is done. Just make sure it all dries properly, and, as they say,
don't do it again.
I would still take the mirror out of its cell and thoroughly dry everything before reassembly. You could end up with rust, or worse even, mold.