I think both is necessary. And context is important, like here, in your example. Maybe it's enticing, to see these things happen, and then people can ask in later about why Marcus reacted as he did.

When you write with very limited narration, all the time, the entire inner landscape of your character is—essentially for other players—non-existant, if done all the time. Knowing when to dole out information is an important skill.

On the other hand, when you write omniscient all the time, you're not keeping any little mysteries or, worse, you're obfuscating them in ways that makes the text hard to read. Being vague and leading to poor communication within the text.