Were you buffed or blocking? Did you have major evasion on? Are you in heavy armor or running high resists? Do you have expectation that standing in a deadly ultimate should be something you can easily live through? Did you try focusing the sorc?
This isn't like the goliath ultimate where the massive damage came with a 60k health raidboss. The sorcs running these builds are glass cannons. It's not all that different from a bombblade or Synergy bomb. You gotta take the personal precautions you can take because this isn't due to change for another 2 1/3 months or so if it does at all.
There's alot of setup that goes into gettng those big ticks, Make sure you are not walking into walls of elements as that is what will start the catalyst for the OL ticks. Block, evasion and mistform will get you out of that situation. focus the sorc, get behind them and keep your feet moving and you will make them crumple.