To create the effect of Ian splitting himself, Entity FX used three difference techniques. First, the primary shot of a CGI face pushing its way through a digital image of Thomas' back in three dimension; second, the team used "shadowplay", which is a two dimensional shot appearing on a wall as though the audience is seeing Ian's shadow as he splits himself; last, the team applied another two dimensional effect to the final moment of separation, when strands of CGI flesh snap back to each body.
In the start of the show on metallurgy class Clark has made an S that it looks exactly like the one on his shield on the Superman suit. When asked about he comes up with "its for Smallville high, the school logo needs an upgrade"
Lex meets Dr. Helen Bryce for the first time.
This episode possibly marks the first time Clark carries someone while in super speed; in this case, he is holding a (conveniently unconscious) Chloe in his arms while he runs back up the dam. While his invulnerability shields him from harm of high-velocity movement, this may be another hint since "Obscura" that he could partially extend it to whatever he touches.
Ian's fate is revealed in the Season Three episode "Asylum".