Apologies for my posts being broken. Bloomin iPhone!!
What I was going on to say was that officers are also taught how to avoid positional asphyxia but it's a sad fact that some people are so violent that they have to be restrained for a prolonged period of time. I don't think it's a good idea for police to let go of these people but I agree, any death is tragic and should be avoided. Bt the police can and should protect themselves and the public from violent individuals.
Each death is thoroughly investigated and the fact that no police officer has been prosecuted for a death of this kind, is proof that they have acted proportionately and have been able to justify their actions.