Stuck on Solitary Riot - What now?

You pick the life shield against Parasite, not the necrotic shield. And an anti-radiation shield against Metallo, not a Kryptonite shield. You're picking a shield that is the opposite of the enemy you're fighting - warmth to protect you from Captain Cold, and cooling to protect you from Heatwave.

But yes, it seems counterintuitive. I certainly wouldn't have figured it out if not for somebody else telling me...

Isn't it a CR 70 requirement just to get the mission?

I think so, but my Controller gear was in the mid 70's. I tried to do it in Controller stance first and got creamed. Had no choice but to put on High Voltage. Needless to say I attuned the rewards to DPS and with the new gear and experience I can generally do these instances without dying. Finally. lol

Hum, i guessed the ice shield protect you against ice effects, fire shield to protect you against fire effects and etc.

Here are my tips, other than making sure you have the right shield
As soon as you get in, grab the heal barrel and take it to the end of the little area and hope that you do not need it during the first part.
After you finish the first part, get the correct shield and open the entrance, go get that heal barrel and drop it in the area near the entrance. make sure it does not get to close to the big block or it might get popped. Then go to the turret and after the little animation, pick up the barrel there and bring it back to the entrance area too.
Use your supercharge heals and hard light shield. Make sure you are fully charged before going in.
I find the backups trinket and the central city trinket to be the best 2 to use. If your belt can hold more, the merrier.
When the boss spawns, you will be transported to the middle of the area. Immediately go back to the entrance. Pop a barrel if needed.
Pop the boss a ranged shot if he targets the turret instead of you to get him to come over.
Beat up the boss. The little guys will most likely stand around or get frozen by the turret. Otherwise, kill them first if they get too close.

So I agree this instance can be difficult, and I have been using the wrong shields too. But I agree this is easier for dps to finish than for some of the other support roles. I run this with my 88cr 97sp Fire tank and get destroyed unless i switch to dps stance and weapons. However I also have a 87cr Fire DPS with 79sp and can do this without to much trouble. I am curious to see how much difference the right shield will make.

TO imply that SP are less important that CR shows that you clearly have no idea.

Thank you for clarifying. I get confused easily.