Arizona Deputy Richard Lopez had eight floors to freedom. But by the time the elevator doors closed and Lopez reached the ground, a shank-wielding inmate had slashed his face 10 times as seven other inmates watched.

Other Maricopa County deputies immediately seized the inmate when the doors opened again in the lobby of Maricopa County Superior Court in Phoenix on Wednesday morning. Lopez had been leading inmates back to Fourth Avenue Jail when Ramon Hernandez Martinez attacked, authorities said.

Martinez had just appeared in court on charges stemming from two home invasions, three car-jackings and a shootout with police. The deputy was taken to Banner Good Samaritan Hospital with non-life-threatening injuries. He is expected to make a full recovery. Martinez is now in solitary confinement and faces additional charges. Authorities believe the attack was part of an escape attempt and he may have conspired with someone else.

It was not known how the crude metal knife in Martinez's waistband went unnoticed. Sheriff Joe Arpaio said the inmates were searched before entering the courthouse, but he could not say whether the scan included a pat-down or metal detector.

Deputies also are investigating why Martinez was using a crutch, which allowed one of his hands to be free. Arpaio said Martinez was not injured to the degree that he would need assistance and was either issued the crutch in error or he took it from another inmate. Martinez was handcuffed to the crutch and nothing else. Another inmate in the elevator was in a wheelchair. The remaining six inmates were strung together by a chain and bound at the wrists and ankles.

Arpaio said it's common for a lone deputy to transport up to 15 inmates. The Sheriff's Office moves about 700 inmates daily and hasn't reported a deputy injury since the mid-1990s, Arpaio said.

"We do the best we can," he added.