Cornered in the Catacombs quest softlocked

Hi, I took on the Cornered in the Catacombs quest. When I went down into the catacombs, they were empty. No darkspawn, no blight, just the area and the environmental puzzles (which worked fine). I navigated through the area, assuming I was in some sort of prelude zone and took the lift to the upper level. Then I was just back in the city.

Later, I fell down a hole and when I respawned the darkspawn did too. I defeated them and went through much of the mission. However, when I arrived at the elevator, it was already raised to the upper level and I couldn't call it down. 

I went back to where I came out and now it was blocked by blight with no way to get around it. It looks like I've locked myself out of the mission.

At the time I did this quest, I was having some performance issues with stuff loading in on a delay, which explains how I was able to navigate thru unchallenged.