The chip can end up sideways in either case really… but the pierce-and-slide is not “make a hole and shove the chip through” it is basically the same as the injector method… the piercing needles goes all the way in, making the same hole/pocket/tunnel… the only difference is you remove the needle and insert the chip vs pushing the chip out the end of the needle. In fact, many people do the injection wrong and do not retract the injector first before expelling the chip, which results in the chip extending past the tip and into unseparated tissue… often with the chip finding it’s own path.
To be clear, the easiest way for a piercer to do this would be to insert piercing needle at least 20mm, remove, manually insert the chip with sterile gloves. The reason for the depth is that the point of piercing needles is often quite elongated and the back bevel is 10mm sometimes back from the tip… and you need to figure your proper pocketing from the back bevel to the incision… so 20mm for a 12mm-14mm chip.
The second method would be to use a piercing needle and taper (metal rod) where the needle goes in, the chip is dropped down the inside, and the taper placed behind the chip. The needle is then removed, while the taper holds the chip in place. The taper must not be used to push the chip out… that’s a bad idea. This method is often done wrong, and is not necessarily any better than the pierce and insert method at the end of the day.