Yes, I should have shielded my camera a bit more to prevent the flare, and in most cases, I would consider such a negative lost. However, in this image, I think it is somehow acceptable, and it doesn't bother me.
Your entire series is really interesting. Exposure and tonality looks well on all of the pictures and they seem really sharp. How did you manage the exposure?
Well, although I have a spot meter and could do a good poking around to find the total scene contrast, with 35 mm film and my Dynax 7 I mostly simply use the multi-segment reading as a guide, and than bracket +/- from about -1 to +3 (of course, there is almost always reciprocity to take into account with old emulsions like TriX 400). This may be a bit lazy, but this way, there is almost always a good negative, and in addition, it helps in finishing the 36 exp. on a roll a bit quicker... I just don't have the patient to wait for the entire roll to be finished before starting to develop them. These are not the kind of scenes you shoot dozens a day from. Usually I only finish two to four shots on an evening.
If it had been LF, I would have done a more careful exposure reading and scene contrast reading using my spot meter.
Lastly, about sharpness: I use a good Manfrotto tripod in combination with 2 seconds mirror lock-up and a cable release.