Its great that the crew survived to fight another day.
However, do consider these fact that the most widely distributed rpg-7 warhead is still the 60's PG-7V HEAT warhead, and by all probability that is what these folks carried.. In todays context of pure armor penetration, that threat has moved away from tanks is relegated to lightly armored. I cannot comment anyting on the IEDs as there is no standard definition fo one, but if i were to take an educated guess, given that the bulk of your force on that route mainly consisted of M113 and the toyota jeeps, maybe the tank was a "chance" target.