He couldn't spare a moment to listen to the music playing through his iPod nano earbuds. Instinctually, he shielded the girl hovering beside him on the rooftop. But that was all he could manage. They were out of time.
Defensive manoeuvres were a luxury he couldn't afford, let alone a counterattack. Ragnar could only brace himself for the inevitable pain that was about to come.
The surprise attack came from an unimaginable angle. The two figures standing on the rooftop of the Norwegian Museum of Science and Technology, whom he had been observing with utmost vigilance, had vanished in a blink of an eye.
A towering, wild figure, well over two metres tall, had silently appeared behind Ragnar and the maiden, who were supposed to be two kilometres away.
"RAGGGHHHHHHH!"
A beast-like roar accompanied the approaching behemoth. Beyond its back, Ragnar glimpsed the underworld ship carrying the Lancer with the Holy Spear.
That ship can hide its path of movement!
This was a flawlessly executed ambush.
Ragnar, the warrior, had no way of knowing the mechanics behind this feat. A temporary dive into the gaps in the world's texture, using the unique properties of the underworld ship. By slipping into these gaps, the ship achieved not only complete concealment of its aura—suppressing killing intent, magic, heat, movement, and all other information—comparable to an Assassin's Presence Concealment skill, but also allowed for high-speed movement.
When it disappeared after the battle at the Oslo City Hall it had indeed, literally, vanished from the world. While inferior to an instantaneous transfer using a Command Seal, it functioned as a kind of pseudo-instantaneous movement. In other words, Rider's attack was a surefire blow, extremely difficult to detect, avoid, or defend against!

Fate/Lost Einherjar, Chapter 3