Give me back my language,
let me speak the tongue you taught me.
I will lie the great lies in your honor...
Ursula LeGuin -- Invocation
It was a polite fiction that the travel through the gate was nearly instantaneous. Near enough to instant that the human brain barely had the time to blink before you stepped out the other side.
But there was a moment: brief, subtle, and solid that was nothing and nowhere.
Carson never knew if he imagined his awareness of this moment. Never knew if he was, somehow, aware enough of the Now that he could see it, feel it, when the universe and his body vanished into atoms and there was only...something. Nothing. The instant in which he failed to be, and somehow found himself again -- moving and breathing and struggling against the urge to run, far as he could from the wide blue orb that seemed so silent when you weren't among its doorways.
He'd overheard Rodney start to talk about how the matter was transferred through the gate. He'd got as far as 'broken down' and Carson knew he couldn't hear anymore, for the sake of Rodney's science grounding it in sense and reality and stripping it of everything that made it true.
He'd brushed Rodney's words aside and said something sharp and dismissive, letting them think him a coward, clodish and sullen at the prospect of the inconceivable. But his fear was only that the words would give shape to something that was already every shape. That math and phsyics might take away the place where every possibility was within sight, if only you had mind enough to cast your fingers out from your designated path and reach them.
So many routes which could carry you elsewhere, visible as you went sailing past, and Carson could remember the first time he'd stepped through the gate and found himself, a moment later, on the other side and wondering why no one had told him he would see the universe sliding by.
He still doesn't know, because he's afraid to ask. Afraid he'll discover that it is his imagination, memories built after his brain is formed again and that there is no way he could know anything, because as he travels, he does not exist.
He doesn't need words to tell him this is the most terrifying thing he has ever known, and if he allows himself to travel more, he knows he will grow only that much closer to the day when he might dial an address incomplete and he will step through the gate to sail among the stars forever.