Powered phoenix rod can fire uninterrupted

In Heretic, the phoenix rod powered by the Tome of Power can shoot fire without intermittent interruptions, which also avoids the ammo cost of resuming the attack.

This is done by firing the phoenix rod normally, activating a Tome of Power, then having the attack button held while the normal attack animation ends and the powered attack begins. The fire is sustained for as long as the attack button is held, and for as long as the Tome of Power effect is active. This can be extended with additional Tomes.

The intended mechanic is for the powered phoenix rod to be able to sustain an attack for a set amount of time, after which it stops and must be fired again at the cost of ammo.