First set of verses says the men:
heard the "sound"
didn't see "anyone"
The second verse says:
saw the "light"
didn't "understand the voice"
"anyone" is not the same as "light"
"voice" is not the same as "sound"
Actually the verses seem to be making the same point, the men that were with him both saw and heard something (light and sound), but they were unable the interpret what the experienced (they didn't see a person or understand the voice). I am obviously doing some reading between the lines here but the principle for interpretation of a verse I am using is what was the author's intent? What was he trying to get across? In these verses, clearly the intent is to express the same message, the men saw, heard, but didn't understand. If that were the message, it is easily understandable that one might express it is slightly, but not mutually exclusive ways.
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