Unfortunately you saved after the bug that was fixed had already broken the quest. I fixed it for you. The ending should trigger when you load this save. If anyone else needs to fix their save at that spot at the top of the elevator they just need to use the console and enter this :
flags["UVETO_DEEPSEALAB_QUEST"] = 3
Any saves from inside the lab should work normally as the bug only triggered at the top of the elevator.
Btw you were not softlocked since you could still move. The quest was just broken. Minor technical difference but wanted to mention it.