Complex sentence: She excuses herself and steps outside for some fresh air, followed by Peter, upon where she notices a similar glow emanating from the windows of apartment 6B in the Rosencrantz building, owned by the widow Mrs. Alice Merchant (Phyllis Somerville).
Split into simpler sentences: She excuses herself and steps outside for some fresh air, followed by Peter. Olivia notices a similar glow emanating from the windows of apartment 6B in the Rosencrantz building, owned by the widow Mrs. Alice Merchant (Phyllis Somerville).