Chauvin, 45, is charged with murder and manslaughter in Floyd's death May 25 after kneeling on him for what prosecutors say was nearly 9 1/2 minutes.
Video of Floyd being pinned to the ground under Chauvin's knee in which Floyd repeats "I can't breathe" as bystanders yelled at police to get off him circulated across social media, sparking worldwide protests against racism and police brutality.
Any "healthy person", he said, would have died in a similar restraint, which he compared to a vise, supporting the county medical examiner's finding that Floyd's death was a homicide at the hands of police.
A fentanyl overdose, in contrast, is marked by a sharp decrease in the frequency of breaths, he said. It was written by members of the editorial board and is unsigned as it represents the opinion of the newspaper rather than the writers. "And what that adrenaline is going to do is it's going to ask your heart to beat faster", Baker said.
Law&Crime Network host Brian Buckmire said it wasn't all bad for the defense, however, noting that Nelson made some headway by establishing that Floyd might have ingested fentanyl just minutes before he died-which Tobin was forced to concede.
On the death certificate, Baker cited "cardiopulmonary arrest complicating law enforcement subdual, restraint, and neck compression" as the cause of Floyd's death.
She also trained Dr Andrew Baker, the chief medical examiner who issued Mr Floyd's official death certificate.
The autopsy itself ruled out heart attack, aneurysm and other causes, and Dr Thomas said it was not a drug overdose death, either.
Thomas said any blockage over 70 percent to 75 percent could be used to explain death, in the absence of another cause.
"You know fentanyl is not causing the depression of his respiration", the expert pulmonologist said.
In that time, Mr Floyd begged for his life, gasping more than two dozen times and repeating the phrase: "I can't breathe".
Both maintained that neither caused Floyd's death.
The restraint on Floyd came after officers struggled to get him into their police vehicle and then pulled him to the ground.
Thomas noted during her testimony that there is no evidence to suggest Floyd would have died that night in May 2020 except for his interaction with police.
However Dr Tobin, an intensive care doctor, said that Mr Floyd's breathing did not slow down enough for the painkiller to have been a factor in his total loss of oxygen.
Chauvin can be heard on video dismissing Floyd's pleas, saying: "It takes a heck of a lot of oxygen to say things". While a death by hanging is a type of asphyxial death, she explained, she wouldn't say "asphyxia due to hanging" - she'd just say "hanging".
All three doctors called by prosecutors from the Minnesota Attorney General's Office pointed to different moments from the video that they said undermined Chauvin's defense.
She said the level of methamphetamine in his system was "very low", prompting her to rule out a drug overdose as the cause of death. No police involvement, no drugs. "Lincoln, if we take John Wilkes Booth out of this ...,'" Blackwell began, before Nelson objected.
In later questions by prosecutor Jerry Blackwell, Thomas told the jury that a pathologist would be wrong to ignore pertinent facts when determining a cause of death, and said hypothetical questions did not aid this work.
For the first time, a seat designated for Chauvin's family was occupied Friday, by a woman. Chauvin's marriage ended in divorce in the months after Floyd's death. Hennepin County District Judge Peter Cahill overruled the objection, but told jurors it was up to them whether they wanted to follow along with Tobin in feeling their own throats.
Thomas and the jury reviewed photos of Floyd's injuries, including those she described as "superficial injuries" to his face, shoulders and wrists that support what she saw in the videos of his death: that Floyd was trying to push his body into a position where he could breathe.