What's going to fail?
Going to failure in an exercise means doing a certain exercise until you can't just continue, and it can be halfway through.
It is not recommended to overuse this technique as it is very taxing in the CNS (Central Nervous System).
You're making a flat supine, and you've done seven repetitions.
You advance to the 8th repetition but you can't lift anymore, the repetition is in the middle and someone has to help you put the bar on the stand.
This is going to fail.