Among all 5 teams, Blake's team was the 1st to make it into the castle, and since they were on the 1st floor, they decided to explore the lower and underground parts of the castle.
Their train of thought behind this decision was that the underground was the best location for the flag because it would be easier for them to get surrounded.
With Blake's speed in disabling arrays, they were able to quickly breeze through the underground rooms, storage space, dungeons, and so on.
On seeing that there was no flag underground, Blake activated spatial corridors that led them to the spatial mark he had made at the window.
[The heat signature of the fingerprints on the window stool is meant to have gone cold by now.] The system said.
"People entered through this window not too long ago." Blake said to his team.
"How do you know that?" Serhan couldn't help but ask.