Answer:
The court ruled against both Americar and Regency Inn, and then Regency Inn won its case against Americar. The nuisance case itself is pretty unpleasant, so it's not worth referring to it.
The fundamentals for the ruling against Americar were that they themselves had drafted the lease agreement and that the clause included in the lease agreement by which they agreed to indemnify Regency Inn was valid. The original lease term had already expired, but Americar continued to lease the offices on a monthly basis. Since they never left the place, the clauses in the original agreement were still valid even though the lease changed to a monthly basis. I.e. if you sign a lease contract and after the original contract is over, you continue to lease the same place, then the clauses from the original contract still apply.
The clause stated that Americar was liable for damages that took place on the leased premises or in their proximity, i.e. the area near their offices. The parking lot was considered to be in the proximity of Americar's offices.