LITTLE ROCK — A federal judge on Wednesday heard conflicting testimony on whether the three-drug cocktail Arkansas plans to use to execute seven inmates this month will cause the inmates pain.

The testimony came on the third day of what is expected to be a four-day hearing in U.S. District Court in Little Rock. Judge Kristine Baker is considering a motion for a preliminary injunction in a lawsuit by nine death-row inmates, seven of whom are scheduled to be executed over 11 days starting Monday.

The state is rushing to execute the inmates before its supply of the sedative midazolam expires at the end of this month. The inmates allege that the state’s lethal-injection protocol and accelerated election schedule will subject them to cruel and unusual punishment and deprive them of adequate access to counsel.

The state plans to execute each inmate by injecting him first with midazolam, then with the paralytic vecuronium bromide, and lastly with potassium chloride to stop the heart.

A witness for the inmates, Jonathon Groner, a professor at Ohio State University and a specialist in pediatrics, trauma and burns, testified Wednesday that midazolam would not prevent the inmates from experiencing severe pain and suffering when the other drugs are administered.

Earlier in the week, two of the inmates’ other witnesses, Dr. Joel Zivot, a professor at Emory University in Atlanta and a doctor specializing in anesthesiology and critical care medicine, and Craig Stevens, a professor of pharmacology at the University of Oklahoma, made similar statements on the witness stand.

Groner also said he opposes lethal injection in general.

“I believe the firing squad is a much, much better option,” he said.

Daniel Buffington, an assistant professor of pharmacology at the University of South Florida in Tampa and a witness for the state, offered an opposing view on midazolam. He said the drug would “induce (a) significant reduced level of consciousness so that the individual would not experience severe pain upon the timely administration of the second and third drugs employed in the procedure.”

Buffington said midazolam, a benzodiazepine, induces sedation rapidly but its effects are short-lived, and for that reason it is not typically used as a general anesthetic for lengthy surgeries. That will not be an issue for Arkansas because lethal injection is a short procedure, he said.

The state plans to inject each inmate with 500 mg of midazolam. Assistant Attorney General Jennifer Merritt asked Buffington how long that amount of the drug would sedate a person.

“At a dosage far less than that, you could expect an hour,” he said.

Merritt asked Buffington about the 2014 execution of Clayton Lockett in Oklahoma, during which it was reported that Lockett was seen writhing and bucking on the gurney. Buffington said that was a problem caused not by midazolam but by human error, when an intravenous injection was placed improperly, causing much of the drug to go into Lockett’s skin.

Groner also discussed that execution and said that although it did appear to be human error that caused the problem, that is a concern because errors in placing intravenous lines are common. The inmates are alleging that the accelerated execution schedule makes accidents especially likely.

The inmates have filed multiple lawsuits seeking to block their executions. On Wednesday, attorneys for Don William Davis and Bruce Earl Ward, who are scheduled to be the first of the men put to death, asked the state Supreme Court to stay the men’s executions while the U.S. Supreme Court considers a case regarding access to independent mental health experts, which Davis and Ward say they were denied.

On Tuesday, attorneys for Marcel Wayne Williams asked a federal judge to block his execution, arguing that his obesity and diabetes make him especially likely to experience pain and suffering during the injection procedure.

Arkansas has not executed an inmate since 2005 because of legal challenges and difficulty obtaining execution drugs.