So the first sample, potentially the most important sample, because the astronauts may have to evacuate in an emergency, so what is the procedure, take the sample of regolith, next to the lander.
Think about this for just a minute, why whould they elect to take arguabley the most important "contingency sample" were it has the greatest possibility of being contaminated by rocket exhaust, plus surface disturbed by rocket exhaust stream?
Why not walk out far enough to assure a pristine sample?