Odysseus' entrance at Sophocles Philoctetes 974

Early references in Philoctetes to the cave's two mouths are cited as evidence that Philoctetes entered from the cave at 219—it is said that Sophocles inserted them to inform the audience that there is an off-stage mouth. This note suggests that the only other mention of the two mouths, just before Odysseus' entrance at 974, is intended to remind the audience of the off-stage mouth so that it is comprehensible when Odysseus enters from the cave. This is speculative, but the coincidence of collocation that must otherwise be assumed should not be underestimated.