For anyone considering duplicating this little road trip, you might want to
consider that although the radioactivity averaged over space and time is
relatively low in the surrounding area, if you inhale just a few radioactive
particles, the radioactivity in the immediate area of those particles, say
within a few cell-widths, can be very high. That's all it takes to start a
cancer growing.
Your DNA has some ability to repair itself, but it can be overwhelmed by
microscopic particles of plutonium and similar. Just because some $49
geiger counter is showing under a millirem doesnt mean the area is safe.