Looking for hidden part in SL

[viper]

Ok, I'm looking for the hidden part in the investigate mission. The hint I have from a website says to find a room with a vent in the ceiling after you switch the gate lock. Shoot out the grate and boost up into the room above. The only think is, I haven't seen a room with a vent in the ceiling. I did see a room with a grate, but there was nothing but ceiling beyond that. did I miss the room with the part? Is there anybody out there besides me who still plays Silent Line that can help?