Until recently I believed that too. However, I came across some discussion which made me realize I was mixing up the sequence. The transmission interruption, which can be clearly heard, didn't happen at that point in the quote; it happened a moment later, after the word "man". The critical part of the quote seems to come through clear. It's more of a linguistic question about how "for a" and "for" may sound almost indistinguishable in Armstrong's accent.