Given your circumstances, I will guess that what the friends are talking about is they don't think that communion-meals should not be conducted away from a literal, gathered association of believers, who vote on things, who have a pastor, etc.
I could envision them disputing whether a military chapel situation, or a gathering of men on a battlefield constitutes "church" in their mind. And since it isn't "church" to them (since "church" is in essence the "received congregational membership"), and communion is for church, then it shouldn't be served.
Non-congregationalist churches and ministers will probably not see it the same way. For example, the Presbyterian minister who is a chaplain, is ordained as an evangelist, and they are commissioned by a presbytery to function in unique situations with the power of a presbytery or session. Thus, he has permission to serve the meal (as a minister of Word and Sacrament) to believers.
At the same time, we tend to put a higher emphasis on the ministry of the Word (rather than sacrament) in extraordinary situations. Unlike RomanCatholics, or sometimes Lutherans, we do not make the service all about the sacrament.