The calculated distance (air line) between Jardine's Lookout and Tuen Mun is approximately 16 miles respectively 27 kilometers.
By car or train, the actual journey to Tuen Mun is certainly longer, as only the direct route (as the crow flies) between Jardine's Lookout and Tuen Mun has been calculated here.
Air line (approximately)
27 kilometers
14 nautical miles