This quote comes under Pācittiya 74 on giving a bhikkhu a blow out of anger.
Buddhist Monastic Code wrote:
Non-offences. According to the Vibhaṅga, there is no offence for a bhikkhu who, trapped in a difficult situation, gives a blow desiring freedom. The Commentarys discussion of this point shows that it includes what we at present would call self defence; and the K/Commentarys analysis of the factors of the offence here shows that even if anger or displeasure arises in ones mind in cases like this, there is no penalty.
Summary: Giving a blow to another bhikkhu when motivated by anger is a Pācittiya offence.