QF have chutes that they can send it down.
These captured bags would have been around when the flight is closed so it takes time to collect bag and boarding pass of pax, bring bag up to the front.
Each bag will have to be manually bag tagged and correctly tagged with the boarding pass, re deliver boarding pass back to pax.
Then pit crew will have to come up(depending on what they are doing as they can't just drop what they're doing to go) collect the bags, reopen the cargo if it is closed, load the bags, weight recalculated, pilots will need new paperwork, close the cargo, wait for the manual loading sheet if the aircraft didn't have a printer.
Get clearance to push back as well.
And that's how it takes 40 minutes.
I need a drink after writing all that