Is it really impossible to surprise someone with a full-round action?

Question

Is it true that not even the person/creature/thing doing the initial action that starts a combat is able to use a full-round action?

According to all sources I can find, the initial attack already is part of the surprise round, so you're only entitled to a move action or standard action; but that leads to an (in my opinion) absurd scenario, so I just wanted to be sure whether there is something I'm missing:

Let's say sorcerer A is hiding in the bushes, 1HP left, waiting to finish sorcerer B (1HP left) off with magic missiles before B does the same to A. Then he suddenly spots sorcerer B - but sadly, he's some feet out of range. Now sorcerer A wants to use metamagic to double his magic missiles range and fire that on sorcerer B ... but now his magic missile takes a full-round action to cast, so sorcerer A cannot surprise sorcerer B with it anymore.

Is this interpretation right RAW-wise or am I missing something?

Answer 1

That is correct. The best this sorcerer can do is start a full-round action. At least, barring something like time stop.

Generally, the game is designed to avoid situations where someone doesn’t even get to roll.¹ In this situation, the game wants to give B a chance to roll initiative, so they have a chance to perhaps respond or escape.

Note that A could choose to sneak closer to B before initiating the attack, so that a standard action is sufficient. That gives B the chance to roll Spot and/or Listen, though. Still, you can do even better by hiding behind something—with total cover—so that you can 5-foot-step out as a free action and then shoot magic missile at B. That really gives B no opportunity to respond, but it requires a specific setup and great timing.

1. _{Though the game doesn't really do a good job of this, as the rest of the answer demonstrates ways around it. And at the high end of optimization, going first is almost always the same as winning a fight. And things like nerveskitter and celerity mean a spellcaster can go first every time, even when they shouldn’t.}

Answer 2

What the game does not specify is what happens if after a surprise round, you still have unaware combatants. For instance, in your example, what if As starting a full round action did not alert B? Ultimately, this is not covered in the rules, so it's up to the DM. The way I rule it is, if at the end of a surprise round, you still have unaware combatants, another surprise round ensues, but that's purely a house rule at this point.

I think KRyan's suggestion that sneaking closer wouldn't spoil the surprise supports this very idea - you would have to use a move action to sneak closer.