Actually, the OPs question is pretty good!
This is NOT a Non-Schengen to Non-Schengen transfer, where it would be all clear (not entering Schengen/Switzerland, staying "clean" airside) but a Schengen to Non-Schengen transfer.
OP will be allowed to fly, and from what I can see, since he technically arrives within Switzerland, they won't force him to head immediately to the Non-Schengen area.
So he COULD "enter" Switzerland (considering he already arrives as Schengen) and spend some time in Switzerland before moving to his Non-Schengen flight, without actually having to quarantine.
Obviously, one would suggest to him to keep his transfer as quick as possible, immediately heading through passport control into Non-Schengen Dock E area, and wait for his flight there, but he won't be stopped from spending some time landside first and stocking up chocolate at Migros or anywhere of his choicing.