The answer to your question is not directly reflected in the cited materials; however, some sources imply that introducing Islamic elements into a context traditionally dominated by another religion can provoke a turbulent and negative reaction.

Sacred Boundaries: The Provocation of Religious Fusion

The answer to your question is not directly reflected in the cited materials; however, some sources imply that introducing Islamic elements into a context traditionally dominated by another religion can provoke a turbulent and negative reaction.

For example, one piece discusses how attempts at mixing religious symbols and ideas could trigger public concerns.

It emphasizes that a space dedicated to one faith is seen as sacred, and any changes to it might provoke a reaction:"What should be done to prevent the Naval Cathedral from turning into a Naval Mosque?

—Make more Russian children!..." (source: link txt). This quote suggests that introducing Islamic elements into a traditional Christian space can be perceived as a threat to national and religious identity.

Moreover, another source underscores concerns about extremist tendencies and fanaticism when elements that do not conform to the traditional concept of spiritual life emerge within the religious environment:
"In sects, where proper spiritual life is out of the question, fanaticism finds the most nourishing environment... And the Orthodox Church offers measures capable of protecting society from the danger of an escalation of religious extremism." (source: link txt). This reaction demonstrates that any non-trivial religious experiment or innovation may be interpreted as a provocation, potentially leading to an escalation of inter-religious conflicts.

Based on this reasoning, one can assume that if lines from Sura al-Ikhlas were recited in a church, it might provoke condemnation and discontent among believers, as well as heighten concerns about the loss of the "purity" of the religious space. In other words, in this context, such actions could lead both to condemnation by traditional communities and to an escalation of interconfessional tension.

Supporting citation(s):
"What should be done to prevent the Naval Cathedral from turning into a Naval Mosque?—Make more Russian children!..." (source: link txt)
"In sects, where proper spiritual life is out of the question, fanaticism finds the most nourishing environment... And the Orthodox Church offers measures capable of protecting society from the danger of an escalation of religious extremism." (source: link txt)