Yeah. There it is. Your while loop is never ending. Move "my.ANIMATION += 8*time_step" INTO the while loop, and you'll have to move ent_animate in there too if you want it to actually do anything.

break works fine, and there's nothing really wrong with using it, except it looks a little confusing. It's maybe less confusing to just write while(my.ANIMATION <= 50) instead of while(1) if....