First, a quick talk about the spells from your spoiler at the top: spellcasting in PT has gone through a few adjustments since the RP began. Currently, spells are broken into three types (regardless of school): Intrinsic, Focus, and Ritual. For intrinsic spells, you can up-cast them by spending more vigor; they don't require material components. For focus spells, you can strengthen them by focusing for multiple rounds; they don't require material components. Rituals can only be cast at one strength, typically have long and involved cast times; these are the ones that require material components.
Castus and Aquila require verbal components, the ability to speak. Occultus, Bellator, and Serpens require somatic components, the ability to move at least one hand. Material components are only consumed for ritual spells.
At each skill tier (Novice, Adept, etc), there are two intrinsic, two focus, and one ritual spell. Aviate is an intrinsic spell, so you can always cast it as long as you can provide the verbal components (a rhyme or poem in Aquila's case).
Cantrips are actually even simpler:
Orisions
As practitioners of the arcane and divine, spellcasters obtain a certain measure of convenience in their lives. These conveniences are referred to as Orisions or sometimes Cantrips. They offer a variety of practical applications which require neither components nor spell slots. Possible effects include the cleaning or soiling of objects at will, the lighting or extinguishing of small fires, or even the manifesting of minor sensory or illusory effects. The use of an Orision is not conducted as a spell but instead is an extension of the spellcaster's ability, requiring only that they possess a Novice level of ability in the spell school relevant to their intended convenience; these are of limited value in combat.
An example of this could be using what Chase knows about Aviate to use a little magic to help hold their balance while sliding on ice, without actually casting the spell to walk above the ice safely.
That aside, let's look at the chapter. Right into the action, and I love that the distraction is nearly as disorienting for Chase as for anyone else. It highlights the desperation in using the explosion. Yet again, Cribbage to the rescue. Of the familiar/contractor pairings I've read so far, these two are by far the most in-synch and the most reliant on each other. I absolutely love the dynamic, and I think I've said that on every chapter thus far.
I really appreciate that we get to see the runner actually running again, and introducing Aviate at just the perfect spot and yes, casting the spell appropriately. As a side note, there's also a novice level perk for Aquila where casting a spell freely adds a temporarily protective barrier around the caster that can absorb one magnitude worth of damage. If Chase had finished the incant just a little faster, it would have blunted that shot.
It should be noted that city guards will typically carry halberds and attempt to capture petty criminals non-lethally. However, in a market like one of the Jewels, they're likely to have privately hired guards who will be more likely to use lethal force. Chase may need to consider turning themselves in to a city guard if it seems like the market guards are going to go for broke. I doubt they actually would turn themselves in, but it would be a thing I expect to flash through their mind.