Dustin is bad enough at reading social cues when it comes to humanoids; trying to discern the Barry's impatience is, therefore, totally out of the question. Thankfully for the little soldier, he's also very preoccupied with his task and doesn't actually care if someone is around to supervise his progress.

[You don't have to,] he taps with an impulsive shrug of his shoulders (and also his fingers, somehow). [Won't take long. Before sunset, at the latest.]