From Destinypedia, the Destiny wiki
This mode is a popular one among Guardians, as it all the buffs mentioned above. Mayhem has been seen combined with Clash and Rumble. The time limit for Mayhem is 10 minutes. Power ammo revamps happen every 30 seconds to 1 minute. Supers recharge at about 15-20 seconds each time, making this mode mainly about abilities and heavy ammo.
Guardians sign a waver that refers to injury liability that would happen in the Crucible match, in Article 6, Paragraph 18, Where it simulates open war and that there is no limit on supercharging light. An individual names "Arcite" assists Shaxx during those matches.