(CNN) - CNN's Chris Lawrence traveled to Guantanamo Bay, Cuba to get a rare, first-hand look at the drastic measures being taken inside the U.S. detention facility to keep dozens of inmates on hunger strikes alive.

The inmates' hunger strike marks its 100th day Friday, and shows no signs of stopping. Some of the 100 hunger-strikers will drink supplements if ordered to, but 30 detainees who refuse to eat are force fed through tubes put up their nose, down their throat and into their stomach.

"It's kind of a tough mission, this is kind of an ugly place sometimes," says a senior medical officer at Guantanamo Bay who has to remain anonymous for security reasons.

As a doctor he stands by the methods used at Guantanamo Bay. When asked if he's concerned the American Medical Association has come out against this practice, the officer responded that "there's a lot of politics involved. And I'm sure there's lots of politics that they need to answer to as well."

CNN obtained handwritten letters from one of the detainees. One reads 'Be tortured and stay detained.' Another quotes a French writer about how "your very existence becomes an act of rebellion." He sounds hopeless when he writes, "The commissions are a joke. If you lose you go to prison for life. If you win, you're held indefinitely for life."

"We don't have a goal to quote 'break the hunger strike.' We do have a mission to preserve life by lawful means," says Gitmo Spokesman, Capt. Robert Durand.

Gitmo officials showed CNN the numbing gel they offer, and say the tubes are thin and lubricated. "Nobody's expressed to me that this hurts," says the senior medical officer, but defense attorneys say shackling a detainee and snaking a tube into his stomach is inhumane.

Cori Crider, defense attorney for detainee Samir Moqbel says her client told her that "he had never felt so much pain like that in his life."