If tracks are all you have to worry about you are good ..
At 5 my nephew would poop on the floor (take off his underwear and poop)
!!!At 6 my son tried to hold his in for days !!!!! and yes there were track marks
We gave our son extra fiber to help "release" ..
It is more than likely a CONTROL issue ..
This is one thing he can control, the when , how, if he poops ..
The more you get angry at him the more he has your attention and the more he might do this ....
If you are really concerned talk to your ped. about it !!
another thing to consider is could hebe constipated.
Other wise I would watch for signs that he had to go and stop everything interesting until he went. we had a lot of trouble with my third having accidents then as soon as she looked like she had to go no matter what she said she needed we would turn off the TV, put away toys ect. that made it easier for her to want to take time out to go to the bathroom (you know . .. because it takes so long and all and our family is so exciting . . . you might miss a lot . . .) Also walking with her up the stairs and keeping her company while she was in there helped.
The truest answer to violence is love. The truest answer to death is life. The only prevention for violence is for the heart to have no violence within it. We cannot prevent evil through any system devised by mankind. But we can grapple with evil and defeat it, but only with love—real love.
He also had the occassional urine accident that was completely unrelated to the bowel issues, just normal "I don't want to stop" stuff. They aren't necessarily connected.