@Marvin From the docs, "If new flow runs are received on the "critical" queue while flow runs are still in scheduled on the "high" and "low" queues, flow run submission goes back to ensuring all scheduled work is first satisfied from the highest priority queue, until it is empty, in waterfall fashion." Does this mean that the critical work will be done first, or can it not skip ahead of flows that have been scheduled?

In Prefect, flow run submission prioritizes queues based on their priority level. The "critical" queue, having the highest priority, will have its flow runs submitted first before any work from lower-priority queues like "high" or "low." This means that if new flow runs are received on the "critical" queue, they will indeed be prioritized and can skip ahead of flows that are scheduled on lower-priority queues, ensuring that urgent work is handled promptly. For more details, you can refer to the Prefect documentation on work pools.