Except, if he's 2 rooms over it SHOULD take several turns to get there. The combat shouldn't be frozen in time while you run around with other characters doing whatever you want.
Edit: Or in proper DND terminology "don't split the party"
You may want to roll in this thread
https://forums.larian.com/ubbthreads.php?ubb=showflat&Number=760775 on the matter of characters staying out of turn-based mode. And Pandemonica been there, their stance is just all the same - they want their videogamey exploit untouched even if there will be a compromise.