During WWI, the Chofetz Chaim was escaping Radin, where he lived, and was traveling with a group of others on a train. The scheduled time for their arrival was Friday morning. During the trip, they were told that, due to the war, the train had slowed down and would only reach its destination just in time for Shabbos.
Now the dilemma arose as to what they should do. Should they get off the train midway, or should they stay on the train till they reached their destination? If they got off, they might have to spend Shabbos in the middle of a field somewhere, which would certainly be dangerous, especially during wartime. Many passengers therefore reasoned with the Chofetz Chaim that they should stay on the train due to the matter of pikuach nefesh.
The Chofetz Chaim replied that he agreed with their claim, and that they could continue on their trip. However, he personally wanted to get off the train before Shabbos, even if it meant “resting” in an unprotected field over Shabbos. He and got off the train, and many others came along with him, though not everyone.
The Chofetz Chaim then went on and explained himself to those who joined him: “The reason for my decision to get off midway was for the following reason. Although in this situation it was totally permitted to stay on and rightfully continue this trip, I don’t want to continue. I didn’t want to give up on the opportunity to keep Shabbos under such circumstances. This is a unique chance to keep Shabbos in such a way; how can I give up on it?!”
The Chofetz Chaim wasn’t obligated to do so; the halachah allowed him to continue on. But, it was out of his love and devotion to serve Hashem that he wasn’t willing to give up on even part of this mitzvah. (Tiferes Shmuel, parshas Vayeira p. 4)
