If #2 goes vertical:
- Cover all Quick Game and Hot Routes by #2 (Hitches & Slants)
- Collision #2 and re-route in the Seam
If #2 goes out:
- Top the Route (Get body in window of #1's curl)
- Be ready for the throw to the Curl or the Flat
If #2 Blocks:
- Drop with depth over #2
- Be alert for check release & screen
- Head on a swivel for routes coming into the seam
- Cannot be out leveraged to the flat
- If no threats in the seam & no threats to the flat expand late to the curl
Simply Put the SCIF player's drop is to "Hang & Bang" in the seam, expand late to the curl, and let the throw take you to the flat.
I have seen film of both the SEAM and the SCIF used effectively. Neither is the "right" nor "wrong". Ultimately it all comes down to what can your team execute.