The broad rainbow light pattern refracted onto Dominic is typical of the sun and certain types of incandescent lights. When the lamp shade falls off, it is revealed to have a fluorescent tube inside, which would emit only a few very narrow frequencies of light.
Nirrti should never have made it out of the gate room without being discovered. Transphase Eradication Rods (TERs) were implemented as a standard scanning procedure during incoming wormholes due to the Reetou at the end of Show and Tell (1999).