1. The ms. has the text placed correctly after Halakhah 11 but with a wrong header, “Halakhah 9”. In the editio princeps, the paragraph was then wrongly inserted after Halakhah 8; it refers to Mishnah 12.
2. The parallels are Šabbat 2:2 (5a l. 31), Erubin 10:12 (26c l. 47), Pesaḥim 6:1 (33b l. 34); Babli Bava qamma 34b, Šabbat 106a, Beṣah 12b, Yebamot 16b, Sanhedrin 62b.
3. “Liable” and “not liable” here mean “guilty” and “not guilty” under the laws of the Sabbath. In the first introductory paragraph to the laws of the Sabbath (Ex. 16:29) only leaving the camp was forbidden. In the Ten Commandments (Ex. 20:10), “all work” is forbidden without a definition of what constitutes “work”. The missing definition is deduced from Ex. 35. That Chapter starts with a repetition of the Sabbath prohibitions and then proceeds with the instructions for the building of the Tabernacle. One concludes that the work necessary for building the Tabernacle is the work forbidden on the Sabbath (Mekhilta dR. Ismael, Wayyaqhel). Then in v. 33 the work of Beṣalel and Aholiab, the builders of the Tabernacle, is defined as מְלֶכֶת מַחֲשָׁבֶת “thinking work”. The only work which constitutes a punishable desecration of the Sabbath is intentional constructive work. Therefore, any purely destructive work is not punishable.
4. Without exception, destructive work without positive effects is not punishable.
5. In the Mishnah here.
6. As the Babli explains, 35a, an intelligent bull which has a wound on its back sets a fire because it needs the ashes to wallow in them to ease its pain.