There are different levels. I am slightly claustrophobic and the oddest things trigger me freaking out. I also sometimes can calm myself down in certain situations. I put some examples below
If my husband were to throw a comforter on top of my face I freak out, because I cannot breath "fresh" air. Trust me he has done it and lets say he won’t do it again because of how hysterical I got.
I can be in closed spaces for short periods of time, but when we were at Disney the other day our monorail section was very crowded, which I could deal with until it stopped in the middle of the tracks to wait for another monorail to leave the station. This freaked me out and I had to work very hard at calming myself down so I would look like Carly. But until it stopped, I was ok. My husband said that a monorail got stuck for an hour the other day, I told him I would crawl over the seat into the other less crowded section if we were there much longer – lol
If I go to get a MRI, I am good with most machines, but this one was more closed in. Both ends were open, so I was still getting fresh air, but I had to close my eyes and talk myself down. I was paniced for the first couple minutes and the only thing that saved me I needed it and there was no way I was starting the time all over again.
Everyone is different and certain things "trigger" a panic mode. Some people can calm themselves down from these panic attacks. Others cannot control them at all. Others are like your first husband who avoid all situations. Depends on the level of claustrophobia. I think that is with any thing though, like my mom cannot get on a stepstool she is so afraid of heights, but others can who are afraid of heights.