I had a single 12 box, and just pushed it till it fell and just hooked the keys.

 

This is way easier than removing the back seat. Unbolt the lower part of the dash, disconnect the harness going to the truck release button, use some electrical wire or even a paper clip and join the two pins on the connector together. I've had to do it a bunch of times on various Lexus cars.

 

I cant exactly remember the sequence of events. But one time I dropped the key in to a trunk while closing it. Therefore locking it there. I remember spending 1.5 hour on disassembling the lock mechanism underneath the dashboard in the dark, by feeling it. Can't remember what exactly I did, but I did get my keys out of the trunk.

 

Or if you are really cool with your lexus dealer, they will cut you a dummy master key from your vin and you can open the trunk. Basically and aftermarket key such as Ilco that will work all the locks but wont start the car since it is not programmed. Cost should be under 10.00

 

Got my keys out!!!
BTW is a total of 6 12mm bolts. 2 on the top behind the headrest, and 4 on the bottom of the back piece seat.

Ps: thank you for all replies