Franklin is willing to be first down the trapdoor and have a look-see. One possibility is to attempt the 'hobbet on a string' maneuver (so his friends can pull him to safety at any sign of trouble).
Franklin's thought process is, if the halflings can snipe one of the beetles before they close to melee range, it will make things safer for our three new "redshirts" (who are not yet battle-tested).