When Langer asks about Gibbs' boat, Gibbs says it is the third, but in numerous other episodes it has been stated that this is the fourth boat (or that the previous boat was the third).
Around the 41:00 mark, Gibbs walks into Abby's lab and steps on Abby's "Gibb's early alarm system". When Abby wheels her chair over to Gibbs by the door, if you look closely, her wearable magnifying glasses go from down on her nose, to up in the air, to back down again.
When the needle fragment is pulled from Lance Corporal Bakr's body by the MRI machine, Ducky says "turn off the power", goes in and plucks it from the bore with no apparent effort. Unless they are quenched in an emergency (in which case there would be at least a minute of loud hissing as the liquid helium keeping the electromagnet cold boiled off and they'd be evacuating the room as a precaution), the magnet component of an MRI machine is always "on" and pulling with the same force. It would require significant force to pull even a needle from the magnet's housing. Ducky might have the strength, but it would require visible strain on his part and likely be difficult to grip.
Slave name is a term used by the so called Black Muslims or Nation of Islam. Most Muslims not being Arabic they do not have Arabic names and do not need to adopt one on reversion.
In the beginning when the marine pulls his pistol the safety is on. The killer takes the gun and shoots the marine. When Tony picks up the gun the safety is still on.
Ducky should know that all Muslims, service personnel and civilians, accept the need for an autopsy because that is the law of the country in which they live and serve. A call to a Muslim navy chaplain would have resolved his crisis of conscience.
At 17:34- There is no such thing as a basic Marine letter substitution code.