In the Materialization Shiritori game with Jibril, why didn't Sora say "Exceed"?

Question

In No Game No Life episode 6, while Sora and Jibril are playing the Materialization Shiritori game, couldn't Sora just have said "Exceed" and it would've removed Jibril out of existence, which finishes the game because "30 seconds"?

Answer 1

The rules of the game were as follows (taken from the wiki, emphasis mine):

Similar to the normal Shiritori rules, each player takes turns to give a noun which does not end with N. The last character of the previous word said must be the first character of the next word to be said. Things that are present will disappear, and things that are not present will materialize. Players cannot cause the direct death of each other by stating the vital components of the body. The noun stated must be a non-imaginary word. Sora noted that words which are non-imaginary but the opponent does not know of can also be used.

You could maybe argue that causing direct death in one go is still permitted, but that would require a word being played that ended with a certain character. A list of all words used (both English and Japanese) is mentioned in the above wiki.

The word used for all the races in the wiki is Ixseed, but some pages still use 'Exceed' and I am not sure which one the official translation uses. In any case the Japanese word starts with an I sound rather than E, so it was not playable during the game. Flügel was also not possible.

One seemingly missed opportunity was saying "Jibril" after Tsumuji was played (The english word used here was 'Squall'). I presume this didn't work because the Japanese characters might be different (I couldn't confirm) or because the rules are ambiguous regarding proper nouns.