Monday Hour One – when others change your schedule at the last minute

I am working on implementing Monday Hour One. I work where I have scheduled appointments with patients throughout the day. On any given day, I may have zero no shows, or I may have 5. I struggle with not spinning off into unproductive activities during these unplanned down times. In theory, it’s fine to be unproductive during that time because nothing else was planned there and the goal of MHO is to get all the things planned into their own slots. The reason I think it is not ideal for me to switch to unproductive activities is that I often have trouble switching back.
Even if I try to do something productive, I sometimes can’t decide what to do. If the patient arrives 10-20 mins late, I still have to see them (depending on the length of appt). So I am usually not certain of having “extra” time until there are just 10-20 mins left.

C: patients can arrive 10-20 mins late and I still am required to see them.
T1: I feel like I’m in limbo.
F1: anxious
A1: ruminate, check system compulsively, decide they aren’t coming and indulge in online wandering, worry about if they do come late how will I stay on time?
R1: not using time productively/effectively for either work or play, just sitting around feeling nervous.

T2: I can’t decide what to do because I don’t know how long I have.
T2: indecisive (“confused”)
A2: try to calculate how long various things might take, potentially engage in some productive activity – sometimes get engaged in activity and either have to interrupt before finishing or make next patient wait while I finish.
R2: Either nothing done or disorganized progress.

Before using MHO, I would sometimes employ a strategy of “just keep working until someone comes to tell you a patient’s ready”. This helped bypass some of the thinking/feeling issues (I guess I was just ignoring the circumstance?), but would occasionally still result in interrupting work or making people wait while I finished work.

Should I try to change my thoughts, or try to just keep working? I am much more likely to know what time it is and when my patient should arrive, etc. with MHO, which makes it a much more conscious decision to switch “back” to just working. And makes thoughts more likely to occur. I like the feeling of flow and this doesn’t flow. Do I need to just live with that, or is there another way of doing/thinking about things that could return to a sense of flow?