Yes: the healing comes in time to prevent unconsciousness, but whether you fall unconscious depends on the actual damage dealt, your current hit points and your Dexterity or Intelligence modifier.
The Immediate Interrupt takes place before its trigger happens, so you are actually conscious when you use the attack.
- Example 1: You are currently at 15 hp and are going to receive a blow
that would inflict you 17 damage. You then use the immediate interrupt and connect.
- Example 2: You are currently at 15 hp and are going to receive a blow
that would inflict you 24 damage. You then use the immediate interrupt and connect.
The rider effect of regaining hit point takes place as you land the blow.
- Example 1 and 2: You hit, but you don't kill the target. You regain 3 hp (Dex or Int modifier) and go up to 18.
Then, the triggering (enemy's) attack hits, and it could actually leave you conscious if it doesn't hurt you much. If this is the case, the Refire the Forge Attack has took place anyway (many immediate interrupt powers are designed for nullifying their trigger).
- Example 1: You take the 17 damage
from the triggering attack. You drop
to 1 hp.
- Example 2: You take the 24 damage from the triggering attack. You drop
to -6 hp and are unconscious.