NCI-H522 were exposed to compound 1 (10 μM) followed by the delayed addition of BMS536924 (added at 0, 2, 4, 6, 8 hours after compound 1). Viability was determined 1 day later by methylene blue staining. Protection from ferroptosis was detected even if BMS536924 was added 8 hours after compound 1, indicated a rapid mode of action.