On the way they met many guards, those were less powerful than the one outside and anyway, it wasn't really important because even a God wouldn't have been able to spot them under the protection of Miguel's force field.
To get past the checkpoints that the Titans were guarding, Miguel had just opened teleportation portals that took them to the other side and that was it.
Once in the laboratory and before separating, Glen provided them all with disks that could scan all kinds of documents, even computer memory, but the Titans didn't have this kind of technology.
Glen was from a world full of this kind of high technology, and all these little gadgets were always a great help when they did this kind of mission, so they split up to find and copy as much information as possible and when they had finished, they hurried to go and rescue these two prisoners.