I like it how there are a lot of elements in the background, but how (almost) none of it intersects the contour of the singer, letting her stand out.
So did you lose detail because T-Max didn’t handle the push nicely, or because of blur with long exposures?
In this particular shot it looks like the focus is simply off. The background is sharp and the microphone (which should be reasonably stable) is blurred. I also realised that musicians have a habit of swaying in tune with the music which make them even harder to capture in long exposures. As for the pushing I can’t say much since I dont know the camera very well, many frames were shot when the meter displayed "low" in the finder and many frames were surprisingly thin (dark). It might be the way the camera handles long exposures in aperture priority or it might be the film not getting enough light. Most of the pictures I took while the speed was still at 1600 ASA were fine though, it might be a clue, it might not.