The unloaded instrument

The courier was punctual, reaching the rehearsal room before any of the musicians. He was cautious when he moved the instrument case, checking that the trolley wheels had cleared the door frame before turning. People often described delivery as though it were simply movement from one address to another. Watching him made that sound incomplete. The instrument had to arrive at the right time, but also in a condition that allowed someone else to do their work.

From the passage, select two words or phrases that describe the courier's care with time and handling.