In airports and hospitals and such, you can often find "multifaith spaces". Is it permitted to pray in them? These "interfaith prayer chapels" are not churches: they're completely neutral rooms and are described as welcoming all religions. Is there a problem praying in the same room as a non-Jew, even if we are not praying together?
I found this answer provided by Rabbi Baruch Rubanowitz from the Institute for Dayanim:
Praying in a non-denominational room (not found)
What is relevant to our discussion seems to be:
Since the room has been set aside for all faiths entering such a room cannot be forbidden on the grounds that a Jew is demonstrating his belief in another religion.
A cross if used as a symbol (like in Manchester) and was not bowed down to or worshiped is OK. If you suspect the the cross was treated as a symbol of worship than it should be covered before proceeding to daven there. Would there be Moslem prayer mats in the room they are not considered tashmishei avoda zara and you are not benefiting from them so that is OK as well.
The linked answer above is very thorough and I suggest anyone who wishes to comment on this post or gain a better understanding of the underlying issues and how the author reached his conclusions read it first.
Additionally I would venture that there are those who are ready to comment saying that the author has adopted several stringent views and there are other rishonim/poskim who viewed Islam/Christianity more leniently. While that is true, however that would only make praying in a Interfaith Prayer Chapel more acceptable not less.
R' Joseph Dov Soloveitchik seems to forbid praying there.
Let me elaborate.
Around 1950, Cornell University planned an interfaith chapel. They decided to include stained-glass windows. Dr. Milton Konvitz wrote to R' Soloveitchik asking whether or not they could depict figures like Joshua and Jeremiah in the windows.
In his reply, which was reprinted in Community, Covenant, and Commitment, the Rav wrote:
I strongly object to the use of an interfaith chapel. The Halakhah is unequivocally opposed to it and this prohibition is even more strict than that concerning human images. [...] I am firmly convinced that it is our privilege and duty, as Jews and Americans, to oppose the Christianization of the synagogue either in its architectural form or in the mode of worship as it would be the privilege and duty of a good Christian to object to the Judaization of the Church.
In "Spirituality and the Art of the Ancient Synagogue", historian Steven Fine comments on the Rav's reply:
There is no discussion of idolatry, syncretism (shituf), or any of the classical categories of the Jewish-Christian relationship. [Why? Because] these categories, which clearly would place Christianity in a negative light, were best unstated in post-war America.
Regarding multi-faith spaces in airports, R Yosef Yeshaya Braun permits (see here)
[...] it would be permitted, provided that the halachos governing any tefillah (prayer) are adhered to (such as that any women who are in view are dressed in a tznius—modest—manner) and that there are no overt icons of other religions (like a cross) present—or they are covered while Jews pray.
R Yirmiyohu Kaganoff permits it as well (here)
If there is no better place in the airport where he can daven undisturbed, it would seem that he may use the meditation room. Of course, I suggest that our readers refer this question to their own rabbonim and poskim.
I personally met R Shlomo Riskin (the Chief Rabbi of Efrat in Israel) in the Vienna airport and asked him, he permits it as long as there are no religious signs.
Don't rely on the name alone and on the generalizations of the Poskim - check it yourself. Here are the requirements and you'll be able to answer this question for any room:
Does it have a bad smell and/or toilet bowls?1
Does it have unmodest women around?
Does it have statues or pictures or mirrors especially on the wall facing Jerusalem that can be seen as worshipped during the prayer?
Is the room clearly affiliated with any religion but Islam, does it bear a name or a sign of a specific idolatrous religion?
Is staying in the room dangerous for any reason?
If the answer is NO to all questions, feel free to daven.
1NB: It seems that only #1 really invalidates the prayer and one should repeat it in another place, while the rest only forbid davening apriori but do not invalidate the prayer if one already davened and one does not have to repeat it.