After the play, N calls you to ask whether E is permitted to pass 4NT after the hesitation, or whether in fact doing so is demonstrably suggested over other LAs (such as showing his number of keycards, leading to a doomed slam). E comments:
"To be honest, I wasn't really thinking clearly when I bid 4♦. It was an atrocious bid on my hand, as it should clearly show something like 6-5 and a slam try opposite a misfitting minimum GF, especially as this is matchpoints. I decided to pass 4NT because I should have passed 3NT in the first place."
W's comment was along the lines of: "I was considering simply giving preference to 4♠ but decided partner had to have a slam try to go beyond 3NT, and I've clearly got enough to go on if he's 6-5".
Your comments and ruling?