Two questions about shinui makom:
1) Regarding the svara of Rav Nissim Gaon that da'at to eat elsewhere in the same building works, is this only if the da'a't is for a specific location in the building or can the mekadesh have da'at of "I'm eating in any other room in this building."?
2) Regarding the svara of Rav Sar Shalom (in the Tur) that as long as you can see the place of kiddush it's considered bemakom seudah, What if it's a situation where you can see the makom kiddush from the makom seudah and not vice versa (i.e. with a two way mirror) or the reverse case?
kol tuv and yeshar kochachem on a phenomenal resource,
Matthew Wieder, Philadelphia, USA
1) Yes, you can have in mind anywhere in the building without specifying.
2) There is no need to be seen both ways, as long as the person can see his
place of kiddush he is considered still in the place of kiddush.
Rabbi Israel P. Feinhandler