I will take a gander at this since MJ is currently being serenaded by dozens of women.
The former new mining law may have already been priced into the stock which could explain why PTQ did not go up after it passed. The call for repeal brings a question of uncertainty to mining in Panama. Markets tend to shy away from uncertainty which could explain the recent SP drop.
I believe the potential for a mine shut down was first raised by MJ for several possible reasons that may or may not play out. When the politicians redraft a new bill, it could include a short term suspension of all mining activities that would supercede other laws. Protestors could also take force at Molejon to impede on operations as well. This is speculative and I would not put a lot on these events happening, but the possibility exists and it only takes a little bit of negative perception to make an issue bigger than it is.
Not sure what becomes of PDI in the near future. To me it's a wildcard that could have positive surprises if played right, but could easily be trumped if the decked is stacked against it.