Entering via HK/Shenzhen land border, leaving from CAN within 24 hour? 24h direct transit ok?

Hello! I will be staying in Hong Kong for a week and then flying to Europe from CAN. Using the 24 hour direct transit will I be able to enter mainland China through the HK border on foot and take a train to CAN for my flight that is within 24 hours of my entry into mainland China?

Thank you!