[aristeides]

What do they have...a Bat Cave or something?

Local garages that will conceal them? (I wonder what's at that mosque) Big trucks that can contain them?

[livius]

I wondered about the possibility of hiding in a bigger truck, too (that is, driving into one), although then I couldn't see how they could do this without being noticed.

The people doing this are enormously familiar with the area roads. I'm sure they've probably been employed in some capacity that involved a lot of driving, or are perhaps independent taxi drivers who might be very familiar with the area and are not under supervision by an employer (I can't imagine any employer who owns a white truck like this not noticing that it was being sought in this case!)