Don't think there is one for (2).
Crimes have two elements : the wrongful act itself (' actus reus') and the state of mind required (mens rea) to make the person guilty. [There are some offences, called 'strict liability offences', where the state of mind, the intent, is irrelevant. These are nearly all minor offences such as speeding]
Each offence is defined with the necessary mens rea stated. This may be a specific intent: with intent to occasion grievous bodily harm, with intent to cause loss to another, and so forth.Or it may be defined as negligent, or reckless, or one of those with an alternative specific intent :damaged property intending to damage it or being reckless as to whether it would be damaged, for example. Occasionally the mental element is not put in terms but is understood, from authority or by other words in the Act itself : did drive dangerously (dangerously includes some element of recklessness ) , did drive carelessly (includes some element of negligence).
Unjustifiable must import some mental element. What did the accused intend when he interfered? If he did not intend what is in the definition, he is not guilty. If he did, but not that the consequences would be so serious, he is guilty but may have some mitigation. Or was he being reckless or negligent in interfering? Then he is guilty,if the definition includes that and if the consequences were reasonably judged as forseeable and likely by an ordinary person, whatever the accused thought, if he thought at all..