Tena samayena buddho bhagavā sāvatthiyaṁ viharati jetavane anāthapiṇḍikassa ārāme.At one time the Buddha was staying at Sāvatthī in the Jeta Grove, Anāthapiṇḍika’s Monastery. Tena kho pana samayena chabbaggiyā bhikkhū uccāsaddaṁ mahāsaddaṁ karontā antaraghare gacchanti …pe….At that time the monks from the group of six were noisy while walking in inhabited areas. …

“Appasaddo antaraghare gamissāmīti sikkhā karaṇīyā”ti.
gamissāmīti → gamissāmīti nisīdissāmīti (pts)“‘I will not be noisy while walking in inhabited areas,’ this is how you should train.”

Appasaddena antaraghare gantabbaṁ.One should not be noisy while walking in an inhabited area. Yo anādariyaṁ paṭicca uccāsaddaṁ mahāsaddaṁ karonto antaraghare gacchati, āpatti dukkaṭassa.If a monk, out of disrespect, is noisy while walking in an inhabited area, he commits an offense of wrong conduct.

Anāpatti—There is no offense: asañcicca,if it is unintentional; assatiyā,if he is not mindful; ajānantassa,if he does not know; gilānassa,if he is sick; āpadāsu,if there is an emergency; ummattakassa,if he is insane; ādikammikassāti.if he is the first offender.

Tatiyasikkhāpadaṁ niṭṭhitaṁ.The third training rule is finished.