The retail has to trade before the flats are finished. Here's how the phasing works.
In a mixed-use tower the retail has to be able to trade before the apartments above it are finished. That single requirement drives the whole construction sequence — the core, the access, and the order the floors come online.
Phasing is scheduled from the first drawings, not bolted on later. Get it wrong and the commercial space sits dark while the residential completes; get it right and the ground floor is earning while the tower is still rising.