I didn't feel comfortable trying to work on some of it before the performance and the rest afterwards. I used to be able to do that at AV, but that was an entirely different situation. I had a lot more experience with what I was doing, so I could better gauge how long it would take me to complete tasks. In this case, I was implementing something in Python, which I don't know very well, and I was modifying someone else's code, which is generally more difficult than modifyng one's own code. There was also the possibility that someone might ask me to make more changes, so I wanted to be around for that. Finally, since I'm still a temp worker (no word yet on my status), I thought it would look bad for me to leave before finishing.
I left messages with my section leader and director around noon apologizing for being unable to make the performance. I haven't heard back from anyone yet so I don't know how it went. Given my circumstances I think I did the right thing. It wouldn't have been such an issue if I wasn't performing the duet. Sometimes, people who are doing solos, duets, etc. are no-shows and our director has to ask other people to stand in for them at the last minute, but at least I gave her fair warning several days ago that I would probably be late and maybe not even be there.
I was able to finish coding so I feel somewhat relieved. I still have to write some documentation and should perhaps do some more testing. After that I will return to the program I was working on before being interrupted by the Python task.