In just two weeks, the space below Jerusalem's Hadassah Hospital has been converted into an underground hospital, bracing for an influx of war casualties.

Rows of hospital beds and medical equipment have been set up in what was meant to be used as a parking garage.

"We have up to 130 beds here, including intensive care beds," Dr. Tamar Elram, director of the Hadassha Mount Scopus Hospital, told ABC News. "Everything that we do here is in total cooperation and agreement with the army and with police and all the other security forces."

The hospital has also been treating civilian victims, like Michal Alon, who was shot in the hand and chest by Hamas militants on Oct. 7 and is now embarking on the long road to recovery, both physically and emotionally.

"We've already got soldiers and civilians who are turning to our ERs, two and a half weeks after the terror attack, starting to suffer from acute post-traumatic syndrome," Elram said.

Elram says one of the biggest challenges they've faced in preparing for what's to come includes manpower. Some staffers are leaving the hospital to go serve in the Israeli military.

-ABC News' Guy Davies and Ines De La Cuetara

Israeli military spokesperson Lt. Col Peter Lerner confirmed that hostages are influencing the plans of Israel's forces.

"Of course the presence of the hostages is at the top of our priority list," Lerner told ABC News. "It is obviously influencing our operational capabilities, operational plans."

Lerner said that while the military has been given the “green light” to go into Gaza, they have not officially been given the command to "go" from the government.

Asked if the window for an operation into Gaza will close, Lerner responded, "There is no choice for Israel."

Learner also said Israeli forces are actively trying to assassinate Hamas' leader in Gaza, Yahye Sinwar, but they haven't found him yet.

As the humanitarians conditions in Gaza become more dire by the day, Lerner said fuel will not be among the aid trickling into Gaza.

"Hamas has over a million liters of fuel in their stockpiles in Gaza -- they are actually not far away from Rafah. All they need to do is give some to the hospitals," he said.

-ABC News' Becky Perlow and Matt Gutman

The father of 23-year-old Hersh Goldberg-Polin, who was taken hostage by Hamas at the Supernova music festival, said he has gained some "strength" from seeing a video of his son on the day of the attack.

"No parent should ever be subjected to this sight," Jon Polin said on ABC News' "Good Morning America" on Tuesday.

Polin and Rachel Goldberg's son was wounded in the Oct. 7 attack. He had been hiding with a group in a bomb shelter and witnesses saw him being loaded into the back of a Hamas pickup truck, his parents told ABC News earlier this month.

Goldberg-Polin's parents said on Tuesday they have since seen a video in which their son leaves the bomb shelter.

"Knowing he spent an hour to an hour and a half being subjected to this massacre and he then gets up with an arm freshly blown off and walks on his own two feet, under his own strength, towards this truck and uses his weak hand, his only hand now, to pull himself onto the truck while bloodied, but looking sort of composed," Polin said. "It gives me a sense of, he's got a perseverance and fortitude that we hope carries him through this."

Hospitals in Gaza are "horrific scenes," filled with killed and injured children and "medical staff working 24/7 with almost nothing in terms of resources and equipment," said Dr. Ashraf al-Qudra, a spokesman for the Health Ministry in Gaza.

Seventy-percent of the victims are children, women and the elderly, according to the health ministry.

The ministry said 12 hospitals and 32 health centers are out of service, with those numbers expected to rise as airstrikes continue and Gaza runs out of fuel.

"It's dire as it can be. The scenes inside the hospital are almost indescribable -- one of our doctors recently had to do an operation on the floor, in the corridor of the hospital, because there was nowhere to do it. The situation is untenable, absolutely horrific," al-Qudra said.

Israeli Foreign Minister Eli Cohen and the Palestinian Authority’s Minister of Foreign Affairs Riyad al-Maliki, gave long, impassioned speeches at the United Nations Security Council meeting about the suffering their people are experiencing.

Cohen began by holding up photographs of the Israeli children kidnapped by Hamas, reading out their names and ages.

"They are just a few the many children and babies that have not seen evil. They have not caused evil. But they are victims of evil," he said.

Cohen described Hamas as "the new Nazis" and said Hamas' Oct. 7 attack on Israel should serve as "a wakeup call against extremism."

Al-Maliki purported that Israel’s retaliation had equated to "ongoing massacres being deliberately, systematically, and savagely" perpetrated against Palestinians civilians.

"The Security Council has a duty to stop them," he said. "It is our collective human duty to stop them now."

He suggested that Israel's campaign would ultimately lead to more conflict, saying "more injustice and more killing will not make Israel safer."

The foreign minister argued that everyone on the council should be united behind one goal.

"We should be on the same side -- all of us who believe in justice and peace," he said. "We should stand shoulder to shoulder in these moments. But that is only possible if everyone recognizes the value of Palestinian life -- the need to uphold Palestinian rights."

-ABC News' Shannon Crawford