Shin, personally, was Schnee’s long-time acquaintance, and Wilhelm had a character that didn’t hold much back. Therefore they could talk normally. However, as Tiera said before, even children knew the name Schnee; she was very popular.
If that person was in front of someone normal, they would probably react this way, too.
“Oi, come on! Don’t we have to go soon? There’s no need to rest here, right?.”