when medics arrive on an accident scene, they don't know if the victim has a spinal injury. It is sometimes hard to remove a tight helmet from the head of a guy without seriously moving his head, further injuring his/her spine.

I read a case about a "good samaritan" getting sued for millions because he pulled an accident victim from a car crash, not knowing she had severe injuries. As a result, she is paralyzed for life. If he had left her in there, a trained medic would have left her there and waited for the firemen to pull the door open.

Hence, since the helmet is there, he probably took it off, or was conscious enough to tell the medics he was alright. Just my opinion.