There’s a story about a Rebbe who was moiser nefesg to break the ice of a lake to go to the Mikvah one Channukah when he was a slave in the work camps. The story goes that a Nazi Y”Sh saw him and was so nispoel he gave him an extra ration of food.
A friend of mine asked the Rebbe directly and the real story was that a beam fell on the lake and cracked the ice. The Nazis offered food to the man who would jump in and lift it out, so the Rebbe did so with the kavona that going to the Mikvah would save him from hypothermia.
The first version is still what I hear all the time when people talk about that Rebbe.