Normally when you press Pause, and then press the Forward button, you go to 1/15 slow motion, but there is a jump in time of a few seconds to the point where the slow motion begins. But I have discovered if you press Pause, then press the Skip Ahead button, then press Forward, you will start 1/15 slow motion from exactly the point where you paused, with no discontinuity.
If you try this, you will notice when you press pause, there will be a white progress bar at the bottom of the screen, then when you press Skip Ahead, (the button that usually causes you to skip ahead 30 seconds in Play mode,) pressing Skip Ahead while paused doesn't make you skip ahead 30 seconds, instead it makes the white progress bar disappear, and be replaced by a small icon that looks like a Pause bar with a Play arrow. Like this 'II>'. You can then start forward (or backward) slow motion from the pause point.