When the SN was built

[Alan Ford]

No

So when do you think the sounds of the ambulance arrival happened?

[Richard Smith]

This thread about the construction of the rifle rest has given a new understanding to what LHO was doing between the departure of the floor laying crew and the arrival of BRW. A big question is what LHO would have done if BRW had actually gone over to where LHO was sitting. Would he have decided to not shoot at JFK or just killed BRW.

Oswald likely scouted and/or knew from his experience in working in the building the various locations that offered the best combintations of seclusion and shooting angle.  If it had turned out that a group of folks were on the 6th floor, he probably would have just gone up to the 7th floor where there would have been no one.  I think the ledge under the 7th floor window might have been the reason he didn't do that in the first place.  Just speculation, though, as it turned out to be unnecessary.

[Charles Collins]

So when do you think the sounds of the ambulance arrival happened?

You can freaking read.

[Alan Ford]

You can freaking read.

Why can't you answer, Mr. Collins?

At what time do you believe the sounds of the ambulance arrival happened?

[Charles Collins]

Why can't you answer, Mr. Collins?

At what time do you believe the sounds of the ambulance arrival happened?

Maybe you can’t read.

[Alan Ford]

Maybe you can’t read.

~Grin~

Maybe I can, and maybe that's why you don't wish to answer the question: What time do you believe the sounds of the ambulance arrival happened?

Another way of asking this question would be: What time do you believe Mr. Oswald heard the sounds of the ambulance arrival?

Another way of asking this question would be: What time do you believe Mr. Oswald was spotted by Mr. Rowland near the SW window of the sixth floor?

Take your pick, Mr. Collins! 

[Charles Collins]

~Grin~

Maybe I can, and maybe that's why you don't wish to answer the question: What time do you believe the sounds of the ambulance arrival happened?

Another way of asking this question would be: What time do you believe Mr. Oswald heard the sounds of the ambulance arrival?

Another way of asking this question would be: What time do you believe Mr. Oswald was spotted by Mr. Rowland near the SW window of the sixth floor?

Take your pick, Mr. Collins! 

This is so typical of the nonsense spouted by the CT and nay sayer crowd. One perceived minor discrepancy and they act like they have completely obliterated the whole thing.   

The timing of the sound of the siren isn’t critical to the theory (and remember this is only conjecture). There was some commotion associated with the epileptic event before the ambulance arrived. It was enough to get Mrs. Rowland’s attention (she reportedly saw it about the same time that Arnold Rowland was seeing the man with the rifle). Between the onset of the epileptic seizure and the time of the arrival of the ambulance there was likely commotion that could be heard on the sixth floor of the TSBD. Perhaps someone calling for help, or a traffic cop stopping traffic by using his whistle, etc. The point is that the commotion associated with the event could have caused him to look to see if the motorcade was approaching. (And unlike you and your silly theories, I present this as conjecture.)