In today's Rambam Yomi Chovel uMazzik - Chapter Six halocho 9 it says
When two people were proceeding in the public domain, one of them was running and one was walking, and one was injured by the other unintentionally, the one who is running is liable, for he is departing from the norm.
If it was Friday afternoon, after sunset (= בין השמשות), when the collision took place, he is not liable. For he has permission to run at that time, so that the Sabbath will not enter when he is not ready to accept it. If both individuals were running, and one injured the other, neither is liable. This applies even on other days.
From the text, it seems that as long as he is running in בין השמשות, he can prevent the arrival of Shabbos. How is that?