That's not the danger. The client is not going to attack his own lawyer. The danger, if any, is from co-defendants. When you have two or more defendants there may be a cut-throat defence. One defendant may claim innocence but blame one or more of the others, saying they did the crime.The others, or their families, might decide to have a go at the lawyer whose client is doing the accusing.
The 'safest' job is that of prosecuting counsel. He or she never gets threatened. That's not because they've got a lot of policemen on 'their' side: it's because defendants think that prosecuting counsel is 'just doing his or her job'. If they are angry at the prosecution, it is at the individual police officers or other witnesses involved, not counsel presenting whatever those people have said.
That all said, it is very rare for defence lawyers to be actually attacked, unheard of really, but they do get threats from time to time (which they ignore, in general, though if it happened in the course of a trial that might well be reported to the police)