What on earth was the point of hanging around past the moment they were reunited? Was there a reason he had to remain captive and be brought into the auction? You have the girls back, so kick the slavers' asses and leave already.
Its not mentioned in the manga, but in the WN theres a reason clarice and misha got themselves captured since in the WN mc believe clarice herself is enough to beat them
Basically misha realized one of the kidnapper is an adventurer that related to her mom (its the guy with funny moustache guarding their weapon) so clarice didnt fight back and got put into sleep using his sleep magic, so they can have a clue where to find misha mother
Hearing clarice got captured, mc realize theres some plan so he also got himself captured. MC also interested with the sleep magic that has been used on her and want to investigate that moustache guy
Well theres more to it but i believe the chapter will cover it soon enough