I have retreat tomorrow should I still work in the morning?

At work we have this one day event called retreat where we just do team bonding games and Organization Development comes in give us personality tests and we have a lesson on stress management. We are not expected to go to work at all since it starts at 8:30 am. Basically should I come in at 7:30 am and do some work and then go to the retreat. I have to leave 30 minutes early to go to doctor's appointment for surgery consultation. My manager did asked me and co-worker if we would be in, in the morning as a general question no particular reason I think. we work in the hospital so our atmosphere is relax.