Immediate actions "can be performed at any time", but how quickly can they be used?
Does it mean a spell like emergency force sphere could be used to avoid (for instance) fireball?
- Wizard Bob sees his arch rival Wizard Zob; at long distance, initiative time!
- Wizard Zob wins initiative and several rounds go by of mage battle.
- Wizard Zob's next round, he decides it's fireball time!
- Bob thinks fast and casts emergency force sphere around himself to stop the fireball.
Can Bob do that?
Looking for answers primarily for Pathfinder, but answer for 3.5 as a bonus (if it's different)