This was new -- Colin had never felt the guards before like others did, simply knew on instinct where they'd be because he spent enough time spent paying attention.

I don't think "instinct" is the right word there -- instinct seems like it's more akin to the magic; what you seem to be talking about with Colin is knowing because he's studied. You could simply make it "[he] simply knew where they'd be because he spent enough time paying attention." (Also, you have two "spents" in there.)

Other than that, I have no real criticisms of this chapter; it works very nicely. I will say, though, that although I loved the little bit with Joseph, I'm still shipping Colin/Noel like whoa.