Stuck in encounter

I recently faced an encounter with a slime monster, but the encounter would not progress. Even if I passed my checks, I could not escape, and when I tried to give in to sacrifice myself I could not do that. I was literally stuck. Then, the NPC suddenly pulled out an item that was not brought up at all and it magically saved the day, but the plot holes were terrible, and it destroyed the entire flow of what we were trying to accomplish.