I was on the Tube and wanted to get my reply in before entering a tunnel. I already corrected it whilst I was underground. I think the point still stands - is

I was on the Tube and wanted to get my reply in before entering a tunnel. I already corrected it whilst I was underground. I think the point still stands - is this really a big problem? I guess I couldn't recite the syntax from memory, because I usually use a utility type for this