The "Preemie" feature in the app allows you to control the levels that SNOO engages. When "Preemie" is turned on levels 3 (yellow) and 4 (orange) are disabled. SNOO will not advance beyond level 2 (green) - even if the baby cries.
When "Preemie" is turned on "Level Limiter" is automatically turned on as well.
If SNOO cannot soothe the baby on level 2 (green) you will be notified that the baby requires your attention.