They never attend a church to be converted, rather they are mandated to enter churches with the idea of converting you.......and we all know the enemy of God is at the door welcoming them in.
I’ve never known someone who I thought was a strong Christian who converted to Islam. I believe that God is able (and willing) to keep us from falling. We are commanded to preach the gospel to all peoples. We should be making the most of every opportunity.
Salvation is of the Lord so it doesn’t matter if a muslim has no intention of converting if God has other plans. If it was up to us nobody would ever be saved.