Seeing, if you think about it - even for mortals - implies a sense of movement. This is because we exist in space and time, and it takes us time to do things while transitioning from one point to the next. To see one thing (A) and then look to another (B) requires a movement in time and space from A to B.
But that is how humans move, not angels, although humans can have a sense of how angels move.
According to Thomas Aquinas, angels move by making decisions, although their decisive process is somehow different because they don’t exist in the same time and space.
Their perception of God is immediate and eternal. They aren’t separated in space by a body, so it seems like they are somehow just “everywhere” at once. Similarly, their decisions (motions) wouldn’t exist in time as we think of it, like when we spend a lot of time deliberating over one thing and then another. Their understanding is simply “right there”.
To make such a decision seems to require knowledge of what one is deciding upon. So how do angels see? It’s probably just by knowing God somehow. I once heard angel’s “compete to do good”. I imagine such competition must be something like burning with charity as they constantly move toward (i.e. decide in favor of and bless) God.
But that’s also probably why, when the bad angels fell from grace, it happened all at once at the very the beginning of creation. They saw God’s entire plan all at once and forever, disagreed with it, and that was that… or, in other words, since what they decided against was eternal, they made an eternal choice, and they couldn’t repent… their “movements” (decisions) seem like they could only be from one bad idea to another…
That’s about the best I can do given what little I know. It may not make much sense, but I hope it helps though.
