Dave Bonta's "Quick study" is a tiny poem that packs in a lot of unease. The first two lines link speed with destruction: something is "fleet as decay," and then we meet "the arson's child." The phrase is ambiguous. It could mean a child of someone who set fires, or it could mean the fire's own offspring, something born from burning. Either way, the child seems to learn fast, which fits the title. A quick study picks things up in a hurry, and here what gets picked up sounds dark.
The last three lines turn to the speaker. They place themselves "in all / knowledge and experience / like a well." A well suggests depth, darkness, and something drawn up slowly, which contrasts with the rushing pace of the opening. The speaker may feel they hold a great store of understanding, or they may feel sunk and stuck in it. The poem doesn't settle this. The mood is quiet, tense, and a little haunted, as if learning always costs something.