Ladybug had been separated from his partner pretty much immediately after getting on the bullet train. So after killing the Wolf, albeit accidentally, he was now sat in front of the dead man eating wasabi peas trying to figure out exactly who he is

You entered the carriage with a expression that was now very confused

“Oh hey you’re back!” he smiled and gave a wave

“Do you know who this is? He tried to wack me, it was all very confusing..”