[from x: accepting]
If the ambiance/atmosphere is right then Kyouhei will be verbal with his fear - either swearing (only done when scared/surprised), making various cliche noises (“gah!” and “wah!”), or will even scream girlishly.
Be warned, though, he has a “fight” instinct… which means his surprised expression will be followed closely by a punch or a kick or another kind of attack….