Booth's visit to the Surratt Boarding House after the assassination

[J. Beckert]

Bill - again, all this is speculation, but Booth didn't need a revolver as his primary target was Lincoln. I don't think he wanted to kill anyone else in the box. I believe the Deringer was the one tool needed for that particular job and Rathbone was not targeted for death. He just needed to be dealt with enough to make good his escape, which as John pointed out, came close to being foiled. The pistols could have easily been concealed on his person. They're just not that big to make that impossible or improbable.