梵網經菩薩戒本疏 5.136

5.136

七、通塞者，若自重病，若無勢力，徒自殞命，終無有益，准應無犯，反上皆犯。

Seventh, regarding permissible and non-permissible cases: if one is severely ill oneself, or lacks the power or influence such that one would only lose one's own life in vain without any ultimate benefit, according to the standard there should be no offense; the opposite of the above are all offenses.