JERUSALEM — Even after four months of the most grueling and gruesome work of his life, the anesthesiologist wanted to stay at his post at Nasser Hospital last month when the Israeli tanks closed in.

But doctors, he fretted, face one of three fates in wartime Gaza: displacement, detention or death.

He’d seen Israeli forces disappear doctors during raids on the enclave’s besieged and collapsing hospitals. He feared being accused of supporting Hamas, being made to strip and sit blindfolded, and seeing photos of the humiliation shared online. He’d heard about the abuse Palestinians endured in Israel’s secretive detention sites for Gazans.

However, the anesthesiologist had six children and a large extended family in Rafah that relied on him. So it was with a heavy heart, he said, that he fled the hospital on Jan. 26 and joined the Gaza Strip’s growing cadre of displaced medical workers.

“There was a lot of gunshots, a lot of destruction, and I had to leave because I have a big family I’m responsible for,” he said by phone from Rafah, where he now lives in a nylon tent. He described his experience to The Washington Post on the condition of anonymity to protect his safety.

The anesthesiologist fled Khan Younis with three other medical workers, but he was the only one to make it south to the relative safety of Rafah. Israeli forces controlled the war-broken roads thick with fleeing refugees, and the trek spooked his colleagues. They headed back to the hospital in two groups. One colleague was shot along the way, the anesthesiologist said.

He believes his three colleagues are now among the 70 doctors, nurses, and medical technicians from Nasser Hospital that the Gaza Health Ministry says have been detained by Israeli forces. He thinks he made it through checkpoints because he was carrying a baby that he found abandoned in the chaos of the evacuation.

More than 100 medical professionals are in Israeli detention, their exact whereabouts and conditions unknown, according to the health ministry. The rest are most likely displaced; like the rest of the population, most doctors in north and central Gaza, scenes of the fiercest fighting for much of the war, have fled their homes and communities for the south, ministry official Ahmed Shatat told The Post.

Most live in tents, Shatat said, where they are receiving partial or no salaries. They devote their days to trying to find food and water so they and their families can survive.

Many fear returning to the medical sector and its acute crises. Gaza’s 2.1 million people are on the brink of famine, according to the United Nations, and infectious diseases are spreading. Ultimately, analysts and aid workers warn, that hunger and disease could kill more people in the conflict than Israeli weapons.

Hamas-led militants streamed out of Gaza on Oct. 7 to kill around 1,200 people, most of them civilians, in Israeli communities near the enclave, and take 253 more hostage, according to Israeli authorities.

Israel’s military campaign, launched that day in response, has killed more than 29,000 people and wounded more than 69,000, according to Gazan authorities.

Now few of Gaza’s hospitals and medical facilities remain even partially open.

“How can we sustain any type of response when medical workers are being targeted, attacked and vilified for assisting the wounded?” Christopher Lockyear, the secretary general of Doctors Without Borders, asked the U.N. Security Council on Thursday. “There is no health system to speak of left in Gaza. Israel’s military has dismantled hospital after hospital.”

Israel says doctors and hospitals provide cover for Hamas militants. The Israel Defense Forces told The Post it was “well documented that Hamas uses hospitals and medical centers for its terror activities.”

Palestinian doctors and international medical volunteers told The Post they have seen no sign of militant activity. Rights groups say Israeli raids on medical facilities and professionals violate international law and have been disproportionate to any threat posed by militants who might have operated in hospitals.

Israel has denied The Post and other international news organizations independent access to Gaza’s hospitals.

Nasser Hospital, once the largest medical facility serving southern Gaza, is the latest flash point in the Israeli campaign.

The IDF said it found weapons and arrested “Hamas terrorists” in the complex.

Doctors Without Borders staff fled the hospital last week. Lockyear said the organization had “seen no independent verified evidence” that hospitals have been used for military purposes.

Israeli forces surrounded the complex in January. Mohammad Harara, a physician in the emergency department, told The Post that overcrowding and supply shortages left doctors to treat patients on blood-smeared floors.

Israeli troops raided Nasser on Feb. 16 and occupied it for several days. The World Health Organization says it’s now “unfunctional.”

In recent days, the WHO conducted three “high-risk missions” to the hospital and evacuated 51 patients to the south, according to Ayadil Saparbekov, acting WHO head of office for the West Bank and Gaza. About 140 patients, four doctors and nurses and a dozen volunteers remain.

“The intensive care unit of the hospital was not functioning,” he told a briefing Thursday. “The hospital did not have electricity. The hospital has no food, no medical supplies; neither does it have oxygen.”

Moshe Tetro, who heads coordination and liaison with Gaza for the Israeli military, said he had visited the hospital and saw no shortages of medical supplies, food, water, or fuel for generators.

Chandra Hassan, a bariatric surgeon based in Chicago, went to Gaza with the aid group MedGlobal in January to volunteer at Nasser. He described it as “a war zone,” with constant shelling and gunfire and days-long communications outages.

“Most of the doctors were displaced from other parts of Gaza,” he told The Post. “They want to spend the rest of the time serving their patients. They don’t have any hopes of getting out alive.”

What scared them most, Hassan said, wasn’t death, but the “humiliation and abuse” of Israeli detention. “They have seen it time and again,” he said. “They are not expecting help from anyone else outside of Gaza.”

Among the doctors detained in a November raid is Mohamed Abu Salmiya, the director of al-Shifa Hospital. Israel said he let Hamas use the hospital as a “command and control center,” but has not publicly disclosed evidence.

Israel has detained hundreds, perhaps thousands, of civilians and combatants in Gaza and has held them without charge inside Israel in a secretive legal framework that rights groups say is ripe for abuse.

Released civilian detainees have told The Post they were subjected to physical and psychological violence, blindfolded and forced to kneel all day, and denied access to lawyers.

Israel reserves the authority to hold Gazans without charge under the 2002 Unlawful Combatants Law, a form of administrative detention that rights groups say violates international law. Israel was holding 606 undisclosed Gazans under the law as of Feb. 1, according to the Israeli rights group Hamoked.

Israeli authorities say they need to use the law to respond to Hamas’s attack. The IDF told The Post it removes combatants “from the cycle of hostilities” and “grants several procedural safeguards and basic rights.”

Rights advocates object.

“One can see the detention of these doctors as an extension to the attacks on hospitals and medical facilities, which are supposed to be protected under international law,” said Budour Hassan, an Amnesty International researcher.

The law has never been applied at such a scale. Whether, when, and how Israel will try Gazan detainees remain unclear.

Israel’s High Court this month rejected a petition by the families of 62 detained Gazans requesting they be granted access to lawyers.

In Gaza, some displaced doctors have set up free-of-charge clinics in camps and shelters for the displaced.

The anesthesiologist works several days a week at Rafah’s Najjar Hospital. Most patients he sees, he said, have suffered catastrophic wounds. Many are dead on arrival or quickly bleed out.

He still doesn’t feel safe. The IDF told some 1.5 million Gazans to flee to Rafah. Now it says it’s turning to Rafah.

Again, the anesthesiologist is cornered.

“If something happened to Rafah, where can we go?”