Upon entering the rotunda, the Sole Survivor will hear super mutants and synths fighting on the upper levels. Directly to the right of the main entrance are two sets of stairs. The closer staircase leads to the upper walkways where the super mutants and dead synths can be found. The rear, candlelit stairs lead to the roof of the rotunda. At the top of the walkways, past the super mutants, there is a trunk with leveled loot as well as an Advanced locked wall safe.
If the Sole Survivor chooses to destroy the Institute in the quest the Nuclear Option, the C.I.T. ruins are destroyed with it. The destruction levels the entire area, creating a crater that floods with water from Charles River. When in the immediate area, the sky will turn green and lightning will streak across the sky like in the Glowing Sea.
Scattered throughout the rotunda are small stacks of perfectly clean, undamaged pre-War books. They cannot be interacted with.
Though the flatbed truck in front of the rotunda only contains empty radiation barrels, it still adds a substantial amount of rads to those around its vicinity.
Despite the Institute being located directly below the ruins, it is impossible to reach through the ruins (except in Ad Victoriam). Under normal circumstances, one has to use the molecular relay to access the Institute.
The following is based on unverified behind the scenes information and has not been confirmed by canon sources.
At one of the entrances, there is a subtle nod to the film Good Will Hunting, where a skeleton of a janitor is found lying in front of a chalkboard where a difficult math problem has been posted, similar to the plot of the film.
End of information based on unverified behind the scenes information.
Playstation 4 On occasion, there may be an invisible super mutant on the second floor. This is not a Stealth Boy effect since the super mutant is completely invisible even in V.A.T.S.. However, it can still be killed and looted. Companions seem to have no trouble targeting the threat.[verified]