Bava Kama3: 6
שְׁנַיִם שֶׁהָיוּ מְהַלְּכִין בִּרְשׁוּת הָרַבִּים — אֶחָד רָץ וְאֶחָד מְהַלֵּךְ, אוֹ שֶׁהָיוּ שְׁנֵיהֶם רָצִים — וְהִזִּיקוּ זֶה אֶת זֶה, שְׁנֵיהֶם פְּטוּרִין.
[If] two were going in a public domain —- one was running and one was walking, or both were running —- and they injured one another, both are exempt.
