But that could easily be the case with a future appointment by that argument?
If you have a morning slot the likelihood is that your surgeon will have other commitments in the afternoon and the unit will be busy admitting the afternoon list patients by 1pm. Day units tend to run a very tight ship.
Are you the same poster having difficulty with your father? If so please just have a snack before bed, tell him clearly that you will be in contact when you are ready ( actually probably the staff will) and take along something to occupy you. You really are overthinking this entire thing. You go in, wait your turn and then go home when you’re ready. All done.
That sounds patronising but it’s just the truth.