Restorative Pose, put a wash rag or heavy sock across your eyes when doing the MRI. I thought I would be freaking, but with sight blocked, I was fine. I've had more than ten of them since the first.
As for the boat, you say it was hot? Well, we react to heat with MS. Many wear cooling vests and cooling hats.
I got bad a week ago when I was out in the sun more than usual in hot bright weather, including looking at the eclipse at sunset. I have to wear Solumbra cloth clothes to block all UV, as I have a sun sensitivity from another disease. The Solumbra clothing is usually comfortable, but in that heat I was burning. So the next night (takes a day for me to get repercussions sometimes) I was spasming and jerking all night, no sleep.

I can't say why but I don't feel a lot of soreness in my legs except when they spasm so much that I have a long-lasting knot in the calf. Then it hurts. Feet hurt due to peripheral neuropathy, but improved.