This is Sanji realising he is up against a sole monster that will brutalise his shit, but Sanji is sticking to his guns and courage of defending G-5. He realises right here he fucked up!
Facial expressions says it all. This is the face of terror and shock, humilation and awe, helplessness and self-doubt, all rolled into one...
You need to look at this face and realise it ain't coming back ever. Only a true artist can make this face materialise