How would you format this?

[JRTomlin]

(Thomas is exhausted. They had ridden, stopped for an emergency and now he has been guarding this doorway for many hours - because they've been pretty much forgotten. So he doesn't quite go to sleep but is kind of half-awake dreaming)

“Thomas, what are you doing?” Lord Gordon said. Thomas jerked erect. Of course, Gordon was not there. He’d been in a daze, his eyes half-closed. He shook his head hard to clear it.

Now since the 'Thomas, what are you doing?' was imagined, should it be italicised, do you think? I don't want it to confuse the reader which it might in regular print.

[Lynn]

I guess it really depends if you want to clue the reader in before you reveal that Thomas jerked awake. If you italicize it's advance warning that something is off. If you just want it to unfold and be a surprise, then I don't think there's any reason to do anything special at all. I wouldn't have trouble with it. I'm not sure anyone would.

[JRTomlin]

I wouldn't have trouble with it. I'm not sure anyone would.

Ah, so I was stupid to ask. Thanks for the head's up, Lynn.

[Lynn]

I wouldn't have trouble with it. I'm not sure anyone would.

Ah, so I was stupid to ask. Thanks for the head's up, Lynn.

Of course you're not stupid to ask! ;D I'm sure someone will come along shortly and say I'm wrong. Then you'll be right back where you started trying to figure out the right way to deal with it. 

[VanessaC]

I think I've done something similar in a recent book, and it works absolutely fine as it is.

I have a head stuffed full of cold, which is probably affecting my thinking ability, but the only bit I found confusing was the switch from: Gordon was not there, to the next sentence being "him" which took me a beat to realise meant Thomas, not Gordon.

[Simon Haynes]

I have a head stuffed full of cold, which is probably affecting my thinking ability, but the only bit I found confusing was the switch from: Gordon was not there, to the next sentence being "him" which took me a beat to realise meant Thomas, not Gordon.

Same!

“Thomas, what are you doing?”
Gordon wasn't there, of course, but Thomas jerked erect as the familiar voice seemed to ring in his ears.

Maybe "echo in" or "reach" instead of "ring in", but that's how I'd handle that sort of thing.

[JRTomlin]

Thanks. Sometimes I overcomplicate things. 🤦