In 369 p. 17, he says 「カオス」 ("kaosu," written in katakana). On 18 the other guy says 「かお...す」 ("kao...su" - it's really same thing but with a pause in the middle and written in hiragana instead of katakana).
I'm sure the one from 370 probably says 「チャオス」 ("chaosu") and 「チャオッス」 ("chaossu"), all in katakana.. Like they say, they're cutesy, childish attempts at pronouncing 「カオス」 ("kaosu" -- correct spelling for "chaos") properly. When a raw comes out I can double-check, but I doubt there's any kanji involved.
**I'm including a note on hiragana, katakana, and kanji in one more VM just in case you need it. Feel free to ignore it if you already know.