Hi Tatiana, that was me.  The bluish light behind Elise/Janet in "The Architect" created a halo effect around her head.  Very much like the halo effect created around Red by the stage spotlight when he watched Swan Lake in Mako Tanida.

This is interesting, as Tuxie400 recently pointed out, Red whispers something here that we never found out about, as in 4.08 with Kirk....I can't remember whether or not there was any kind of halo effect with that.