Agreed on involuntary muscle movements being weird. One of the two times I had a panic attack during physical therapy is when they had me hooked up to a TENS machine (little electrodes giving zaps to muscles) and it hit on this one neck muscle in a certain way that it kept twitching strongly. I was alone in the room, they weren't due to come back for 10 minutes, and I was freaking out because it was such an odd sensation (I think they'd just placed it a bit wrong or had it dialed up too high). I could have called for someone, but being like, "heeellllp!" seemed a bit extreme. But I was freaking out.