Criminal
Inside this giant mouth is a person, trapped, because they're a criminal. They did something bad (they touched the mouth of another person without consent) and now they're in mouth jail for criminals.
Picture the criminal, trapped inside the mouth. They don't even look sorry!
しゅう
とら
None
The criminal is only wearing shoes (しゅう). They're completely naked otherwise. They have to wear shoes because the mouth jail would be too slippery for them to stand otherwise.
Wearing nothing but shoes is also really uncomfortable too, so it's actually part of the criminal's punishment. They don't seem to know that though.