.... Just a note about the detonations ... They occurred about 300Ft (90 meters) and apart 10-12 seconds apart ..... still quite a distance.
I would guess, if they really did use toy car radios, that they either picked two with different frequencies, or tweaked the frequencies, or used the PCM (Pulse Coded Modulation) of the signal to detonate the two at different times. Think right/left, go/stop functions on a toy car. That's 3 active functions at a minimum.
Or just used on signal with a delay, intentional or not, on one of the bombs.
What I'm saying is that technically, I could cause a remote event using toy car radios a block away, and time them however I wanted.
I certainly wouldn't want to do that to innocent civilians, but if you want to set up a test, get a spot of desert, and some jihadis, and I'll make their shock collars go off from a couple of hundred meters away.
/johnny