“No Evil Will Befall One Who Fulfills a Mitzvah”

When the Steipler, zt”l, was a young man, he was trapped in communist Russia along with many other yeshiva bochurim in the many branches of Novardhok. Eventually he decided to attempt to cross the border along with a large group of students who wished to go to what was officially Poland. Of course this was dangerous, since if a border guard caught someone trying to cross the border he was within his rights to shoot to kill. Indeed, many people were killed while trying to escape the “worker’s paradise.”
When one group was already well on their way in the middle of the pitch black night, the Steipler suddenly needed to relieve himself. Although he knew his group would not wait for him and he also did not even know the way to the border, even if there had been any light, the Steipler immediately stopped and relieved himself. He reasoned that the dictum, "שומר מצוה לא ידע דבר רע"—“No evil will befall one who fulfills a mitzvah,” also applies to the mitzvah of לא תשקצו. After all, why was this prohibition any less important than any other?
When the Steipler finished, his group was far ahead of him yet he began to continue in what he thought was the same direction they had been travelling for quite some time. In the morning, after many hours of travel, he found that he was back where he had started and it took a whole year before he finally was able to escape to Poland.
He later explained that the first time when he had attempted and failed, he obviously did not have the merit to escape. It was only after the next Rosh Hashanah that it was decreed from heaven that he could cross over into Poland.