The S115 has multiple activities that are called timing-activities which require exclusive access to certain hardware resources. These timing-activities are time-multiplexed to give them the required exclusive access for a period of time. This is called a timing-event. Such timing-activities are Bluetooth® Low Energy role events like events for roles, NVM API usage, and Radio Timeslot API timeslots.
For more information on the scheduling of timing-activities and on-air timing, see Scheduling in nrfxlib documentation.