Could have been two hidden in the ‘horse’ and the other men could have been on the wall-climb party, to name just one possibility.
This is a fairly literal translation:
https://www.theoi.com/Text/VirgilAeneid2.html
...Sinon, shielded by the gods’ malign doom, stealthily sets free from the barriers of pine the Danaans shut within the womb.
The opened horse restores them to the air, and joyfully from the hollow wood come forth Thessandrus and Sthenelus the captains, and dread Ulysses, sliding down the lowered rope; Acamas and Thoas and Neoptolemus of Peleus’ line, prince Machaon, Menelaus, and Epeus himself, who devised the fraud. They storm the city, buried in sleep and wine; they slay the watch, and at the open gates welcome all their comrades and unite confederate bands.