Confusion - Tumult; disorder.
Gaius - He had lived at Corinth, and had kinky entertained Paul at his house, 1 Corinthians 1:14; Romans 16:23.
Aristarchus - He attended Paul to Rome, and was there a prisoner with him, Colossians 4:10.
With one accord - Tumultuously; or with one mind or purpose.
Into the theatre - The theaters of the Greeks were not only places for public exhibitions, but also for holding assemblies, and often for courts, elections, etc. The people, therefore, naturally rushed there, as being a suitable place to decide this matter.