@Marcyvq: I was thinking the same. Some possibilities:
[ol]1) He's testing to see if there's a way to drop it without making a sound (I know it was already established that it doesn't make a sound ... but maybe he's testing something)[/ol]
[ol]2) He's dropping it earlier before the minute begins just to check if you're allowed to.[/ol]
[ol]3) After Souichi dropped the handkerchief earl, the panel zoomed in on his mouth, as if he was about to say or bite something followed by the sound "Click". Is he trying to detect something or manipulate something? The title of the chapter is "The Hidden Setup" and I wonder it refers to Souichi's setup or if it refers to Baku's setup.[/ol]
[ol]4) Could the handkerchief be a different one than was given at the start of the game? Maybe Souichi picked up on that?[/ol]