The actor admits he started planning his escape as soon as he arrived at the lockdown facility, which was six miles away from the nearest road, and to cope with the prospect of swearing off drugs, the first thing he did was get high.
Sizemore tells U.S. news show Access Hollywood, "I spent a whole night where I took some drugs and they didn't know it, so I'm pretending to be drug safe but I'm not.
"What I'm doing is I'm thinking I'm in a movie with no camera. I'm casing the place out like The Great Escape - I'm timing the lights, so the guards won't see me and I've gotta jump over the fence... I'm jumping over barbed wire.
"There was a car waiting for me... and I went home and I got high for two days."
But Sizemore quickly realised he couldn't escape his court-ordered rehab, and so he called the facility's bosses and asked if he could return.
He recalls, "The woman's name was Rosie and she went, 'Are you nuts?' I said, 'I've gotta be there for 58 days, I just took the weekend off.' She said, 'This is a lockdown facility, you can't take breaks. Are you using?' I went, 'Of course.'
"She said, 'I'm gonna let you come back... because you told me the truth... but if you leave again you can go to jail.'"
Sizemore did break out again before his rehab stint was up and spent years battling substance abuse issues and legal problems before he got serious about getting clean. He now insists he's sober.