By the closing day, the purchasers lawyer would have received the keys from the seller's lawyer's office and funds from the bank would have been requested. The purchasers would have already brought their portion of funds to the lawyer.
Once the funds are received from the lender, the purchasers lawyer will get the funds to the seller's lawyer's office (A certified chq delivered by courier or direct deposit to their trust account). Once they receive the funds and related paperwork, they will electronically sign the transfer deed for release and the purchaser's lawyer will register the transfer deed and mortgage.