Anyone who needs a tattoo to explain the Bible to someone clearly isn't educated enough about it to call themselves an evangelist or witness. Christ didn't need that nonsense to explain the scriptures to somebody, and neither did any of the other apostles or the actual evangelists of the 1st century. One of the many problems with Orthodox Christianity is that its adherents think their desire to convert people justifies disobeying God, but the reality is that Satan has those people exactly where he wants them:
"Tattooing is often a magical rite in the more traditional cultures, and the tattooist is respected as a priest or shaman." - Michelle Delio
"When the designs are chosen with care, tattoos have a power and magic all their own. They decorate the body but they also enhance the soul." - Michelle Delio
"The reasons why puncturing the skin should be regarded with some degree of awe are not far to seek, for in the first place, there is the drawing of blood, which to the savage world over is full of significance as a rejuvenating and immortalizing factor. There is in addition to the opening of numerous inlets for evil to enter. . ." - Hambly Wilfrid
"The origins of tattooing came from ancient magical practices. . . " - Laurie Cabot
"[Tattooing] "In association with sun-worship, megalithic building, ear-piercing, serpent worship, . . ." - Ronald Scutt
Those quotes show that tattoos involves the worship and invocation of demons, and is inextricably tied in with the worship of false gods. There is a reason why the Bible explicitly warns Christians against being involved in such activities. People who get tattoos are foolishly inviting evil forces and spirits they don't understand into their bodies, regardless of their intention. This is not a game, and no one calling themselves Christian should be treating it as such. When God says don't get tattoos for any reason, it is for our own good as human beings to obey that command.