Shooting of Good Samaritan caught on tape

A Good Samaritan says he was just trying to make sure no innocent people got hurt when he blocked the door of a Houston convenience store from the outside as two robbers tried to flee.

One of them shot Jeffrey Williamson, who says he's a former Marine, in the shoulder. The bullet went through the glass door and his shoulder. The crooks then took off.

It was all caught on surveillance video. The two robbers are still on the loose.

Williamson told CBS affiliate KHOU-TV in Houston, "Just to get their attention, I just walked out. They confronted me, and I didn't say anything - I just walked out. I closed the door, and the guy was still saying whatever he was saying - curse words, whatever - and then I just stood there, and that really irritated him. And I wouldn't let him out."

KHOU reports Williamson said the suspect got angry and started kicking the door. Then, the second suspect, who had the gun, came over to the door and fired the gun.

"The bullet went in and out," Williamson told KHOU. "I didn't notice at the time, but it's nothing compared to what happens in the military."

Williamson said he stood up to the suspects because innocent people's lives were at stake.

"Those are people's lives ... I would do the same for y'all," he said.

Doctors say he'll recover from his wound.

CBS News correspondent Jeff Glor reported on the robbery on "The Early Show" Friday.