Zack was definitely in no position to hold being a mutant against anyone. He supposed he might be a mutant, too, after a fashion, although he hadn't come by his differences naturally. What was a mutation, anyway? He wasn't clear on the actual scientific definition. He wasn't clear on science in general. Not that he wasn't smart, but he didn't spend a great deal of time in deep thought or poring over heavy reading.
"No problem. Your secret's safe with me. Do you think you could return the favor? Don't tell anyone about SOLDIER unless I give you the all clear? It's a big deal back home, but no one in this area seems to think anything like it is possible. At least, not the people I've met so far."