Trek FX 2 Gen 4, Front Thru-Skew impossible to remove?

Hi all,

Looking for a little help here. I got the bike a couple of months ago, but have just moved into a flat that requires me carrying the bike up a very narrow set of stairs and it's near-impossible to do with the front wheel on, so I was hoping to be able to remove it to make it easier and save the poor walls.

According to the specs, it should be a 5mm Thru-Skew, and I've tried taking it off with a 5mm allen key – the key fits, but it's incredibly stiff and will make a very loud click after a good amount of pressure turns it very slightly. I managed to turn it a few clicks in a row and then there were sparks coming from where I was turning.

Am I missing something about how this is supposed to work? Or am I just being too delicate/precious with it and should just go for it? Every video I can find online (which all seem to be from one person who has just cut their video up into multiple shorts) seems to be about removing the rear wheel only. Or maybe I've misunderstood something and this isn't and easily removable wheel at all.

Any help or advice greatly appreciated!