• The Gaza Strip is under its sixth day of bombings by the Israeli air force.
• Israel on Monday ordered a total siege of Gaza, cutting off the water, food and electricity for its 2.2 million residents, which is a classified as a war crime under the Geneva Convention.
• Israel has ordered 1.1 million people to evacuate northern Gaza, but they remain trapped in the blockaded enclave.

How do you run from bombs when all your borders are sealed off? 

In the Gaza Strip, a small stretch of land blockaded off with concrete walls and barbed wire fences and whose last remaining border crossings have been shut, survival is increasingly a game of chance.

"It's insane and brutal — I can't believe they're doing this to the whole population. The amount of airstrikes are massive," Omar, a Gazan development worker with two young children, told CNBC via voice note. "We're OK for now but it's very scary, and with each bomb we feel it's going to be our turn." Omar asked that only his first name be used out of concern for his family.

Without bomb shelters, people try to hide in hallways, away from windows, in schools, or even in the street alongside piles of rubble. But those spots aren't safe either, Palestinians in Gaza say.

The Gaza Strip is under its sixth day of bombings by the Israeli air force since Oct. 7, when members of Hamas, the Palestinian militant group that governs Gaza, launched an unprecedented terror attack on southern Israel. The highly coordinated assault killed more than 1,200 people, wounded 2,800, and saw Hamas take some 150 hostages, both civilians and soldiers, in what has been called "Israel's 9/11."

Since that day, Israeli officials have vowed to obliterate Hamas using any means necessary as the group continues firing rockets at Israel. But some of the tactics, which are incurring an already dramatic civilian cost, are classified as war crimes under the Geneva Convention, human rights groups warn. 

The Israeli hostages are meanwhile still trapped in Gaza, an act by Hamas that U.N. experts have also condemned as a war crime. Experts at the organization have also strongly condemned the brutal crimes committed by Hamas, and the "deliberate and widespread" killing of innocent civilians.

Israel on Monday ordered a total siege of Gaza, cutting off the water, food and electricity for its 2.2 million residents. On Wednesday, its only power plant ran out of fuel. 

At the time of writing, the Palestinian Health Ministry reports that more than 1,500 people in Gaza have been killed with 6,600 injured. 

'A living hell'

The public water supply has completely run out, Omar said. "We have one tank which we're consuming from. We will run out of water at some point but we're minimizing the consumption to the very minimum." 

Earlier in the week, his father got an automated call from the Israel Defense Forces giving him a five-minute warning to leave his home as the building was about to be bombed.

"Five minutes to leave your house. You can have a final look and that's it," Omar recounted, sending photos over WhatsApp of an apartment building reduced to a mountain of gray debris. "This is my family's house, the house of all my childhood memories." 

On Friday, the IDF issued a 24-hour deadline for the 1.1 million residents of northern Gaza to evacuate to the south, with Israel expected to launch a large-scale ground offensive in pursuit of Hamas. The U.N. warned that it is "impossible for such a movement to take place without devastating humanitarian consequences."

Omar and his family were living in the north, and are now among the estimated 423,000 people who are now displaced.

"Every day feels like a living hell, but somehow the next day is even worse," Omar said. 

"The airstrikes have been wiping out entire families and neighborhoods within the Gaza Strip," Afaf Ahmed, a 21-year-old student from northern Gaza, told CNBC via social media. "They've been targeting residential towers, schools, educational institutions, ministries, most markets." 

A spokesperson for the IDF wasn't immediately available for comment when contacted by CNBC. Officials have stressed that Israel gave Gaza's residents advance warning to evacuate.

"Evacuate where?" Afaf exclaimed. "There is nowhere to hide from the bombs!"

"When Netanyahu said leave, he knows exactly what he's talking about," she said. "He knows that the Palestinians in the Gaza Strip can't leave." 

Meanwhile, Israeli Prime Minister Benjamin Netanyahu said Friday: "We're hitting our enemy with unprecedented force ... This is only the beginning."

Hospitals at 'breaking point'

A major fear Gazans have is the depletion of medical supplies and loss of power to hospitals, which are already overrun with bodies. Once the fuel runs out, the hospitals' backup generators will stop working. 

"Before the war, the Gaza Strip only got six hours of electricity on a daily basis. Now we only get three to four hours and the situation is expected to get worse because Israel is not letting fuel in," Afaf said.

The World Health Organization on Friday warned Israel's siege and bombardment have pushed Gaza's hospitals to the "breaking point," calling for an urgent humanitarian corridor to allow supplies and health workers into the territory. 

"What we are witnessing is really beyond imagination. The toll this war is taking is really huge and seems unprecedented," the U.N.'s special coordinator for the Middle East peace process, Tor Wennesland, said. He warned that the failure of the sewage system was another impending disaster. 

Many of the Palestinians in Gaza CNBC spoke to said their biggest fear was losing their families. 

For Mohammed Ashraf, a photographer in Gaza, that fear has already become reality.

"My niece was killed yesterday by the Israeli occupation army, as well as her two children, and she was pregnant," he said. "They bombed the house over the heads of the civilians in it."

Shortly before the war broke out, Afaf got engaged. She said she fears not being able to experience the rest of her life.

"I just got engaged a few weeks ago so I really want to live. I want to live every single little detail of life. So yes of course I'm afraid of death. But living under oppression and living under these attacks all these years has taught us to be very strong."

"Obviously we didn't get used to this at all," she said. "I can never get used to losing family members. I can never get used to looking at my house, at my room for the last time when I evacuate. I can never get used to searching for my friends trying to reach them and having that fear that they might be gone."

Omar says his primary focus is trying to keep his 6-year-old daughter and 8-month-old son calm. 

"No family should be in this situation," he said. "I really feel powerless, I don't believe anyone will stand with us. This is collective punishment, it's illegal under international law … you are collectively punishing a population for things which they haven't done as people."

For years, human rights groups and U.N. officials have described Gaza as "the world's largest open air prison." Israel's blockade began in 2007, but its occupation of the strip began in 1967, which the U.N. says remains in violation of international law.

"Gaza has always been a giant prison," Omar said. "Now it's becoming a giant grave."