Morgan and Prentiss refer to the outlet in the bathroom as "GFI," when in fact, the correct term is "GFCI" (for Ground Fault Circuit Interrupter). Someone who has installed them in his/her house (such as Morgan) would know this. Additionally, they say that any surge of current will shut the outlet off. GFCI outlets actually shut off if they detect more current flowing out of the hot (shorter) slot than flowing into the neutral (longer) slot. Circuit breakers shut off if current surges, not GFCI outlets.
When Prentiss calls Garcia to ask about temporary paralyzing drugs, Garcia has the "suicide notes" from the case on her computer screen. The top one starts "It doesn't matter that your child is dead. It doesn't matter that your wife is sad..." Then when they find the gunshot "suicide" victim, the note they find with him is the one from Garcia's screen earlier on!
When the team raids the unsub's place and finds the business cards and name tags he has posted, one is for a Tammy Manuelson in Pittsburgh with phone number 415-555-0188. Pittsburgh's area code is 412, not 415.
Neuromuscular blocking agents such as vecuronium bromide and suxamethonium chloride (succinylcholine) are paralytic drugs that paralyze lung muscles and stop breathing for 15 minutes. The victims would not be conscious after being administered one of these drugs unless they were intubated to allow oxygen flow to their lungs, hence their bloodstream and brains. Death would result quickly. See Gizmodo's article on "Sux, the world's most discrete murder weapon" for an example explanation.