Draw reins after a flat tire

I got another flat tire on the trailer; this one just a few miles after leaving the barn.  It took a couple hours to get fixed, so I was quite late for my lesson.
John had us ride in draw reins, and Duke was sweet.  We did a bit of lateral work, a couple leg yields and then some canter serpentines (just to the quarter line and back).  John said that he was surprised by how quiet Duke has been, and me too, for how consistent we were all winter and how erratic my schedule has been for the month of August.  It's kind of a relief, so that if my work life gets crazy in the future, it might be easier on Duke than I thought it was going to be.  On the other hand, he was NOT happy about being in the trailer during the flat tire, and then scraped his nose up on the drive home.
During the lesson, John mostly had me work on making him more round, using half halts, an inside bend, and keeping the connection with my outside hand.