Once of the things you want to remember regarding Lt. Zimmerman's testimony about 'lol there is not threat if they are cuffed, knee to the back is lethal, duh!' is that while it is false and harmful to the defense we have to remember two key factors.
1) This is early during the trial, with deliberations weeks away. It can't make that much of an impact.
2) This is a prosecution witness, so the defense is in a weak position to counter it on cross.
The best outcome for the defense is to wait until they call witnesses, bring up a use-of-force expert, and allow them to talk.
"Mister Use of Force expert, we've heard that what happened was wrong and criminal and against policy. Was it?"
"No, it was totally appropriate."
"I'm an attorney and not able to testify or offer information, so you can tell the jury why you disagree?"
"Well, unlike the retard the State called, I looked at all the evidence, not just a snippet of video."
"For example, he stated that a cuffed suspect is not dangerous. Here are five cases where a cuffed suspect killed the cops and then ate a baby."
"He also stated that once a suspect is unresponsive or stops struggling, they are no longer a threat. Here are five cases where a suspect faked a medical issue, went still, and then killed the cops before raping an adorable puppy to death."
"Despite this, it has been claimed that such a hold was illegal and against policy. Is that true?"
"No. According to these manuals, these training materials, and these videos the Minneapolis police trained Chauvin to use this hold in this exact circumstance."
"Isn't this hold dangerous though? Did the city train my client to kill niggers?"
"This type of restraint is safer for everyone, as these documents and studies show, several of which were included in the city's records. Everyone from the city to individual officers understood that this restraint was chosen for safety."
Waiting allows the defense attorney to have an able expert witness kneecap and execute the weak testimony at a time when a lot more pertinent information can be given, and get it all done days - not weeks, before the jury starts to deliberate.
As Legal Insurrection notes:
There are, of course, limits to what defense counsel can do on cross-examination—specifically, defense counsel is not permitted to argue with a witness (despite what you see on television), nor can defense counsel himself testify (again, despite what you see on television).
These limitations were illustrated when Nelson asked Zimmerman if there was any provision under MPD policy in which a knee on neck would be allowed, other than as a purely opportunistic defense technique, and Zimmerman replied that there was not.
Well, having looked at the actual MPD policy and training manual, I can state with certainty that knee on neck is explicitly permitted (or was, at the time of the Floyd event), and even demonstrated photographically.
Now, Nelson could have pulled out that policy, and shoved it in Zimmerman’s face to impeach him on the stand, but today was not the best day to bring that particular club to bear, and especially not to an older gentleman like Zimmerman.
Best, I expect Nelson thought, to save that club for better time when he could bring it to bear from position of strength, rather than on cross-examination—and at time much more proximate to jury deliberations.
It’s worth keeping in mind that everything happening in court today will have been three weeks in the past by the time the jury goes into deliberations, and in the intervening three weeks the jury will have seen a mountain of additional evidence—much of it evidence presented by the defense in its case in chief.
