The attack drone should fly to a virtual target that is always at 29/30 of the way from the center of the room to the target. That point moves 3.3% slower than the target drone.

Since the attack drone flies only 3% slower than the target drone, it can reach that virtual target in a finite time regardless how the real target moves.

Since the maximum distance from the center to any place of the room is a convenient 30 meters, when the attack drone reaches that virtual target, it is at at most 1 meter from the real target.

And Zap!

The attack drone should fly to a virtual target that is always at 29/30 of the way from the center of the room to the target drone. That point moves 3.3% slower than the target drone.

Since the attack drone flies only 3% slower than the target drone, it can reach that virtual target in a finite time regardless how the target drone moves.

Since the maximum distance from the center to any place of the room is a convenient 30 meters, the distance between the virtual target and the real target is never more than 1 meter. So when the attack drone reaches the virtual target, the real target is in range.

And Zap!