A couple of questions about wraith's "slip into shadows" power (not 100% on the name. It's the one that let's her sprint when attacked). First, what is meant by "the attack is impossible"? My best guess is as follows:
a) She is no longer adjacent to the source of a Melee attack
b) She is no longer within the radius of an Area attack.
c) She is no longer within line of sight to the attacker.
I'm pretty sure about c), but sketchier a) and b).
Also, I wonder how this interacts with "Drawn to the flame" and "hypersonic assault":
Drawn to the flame states the push effect, then says "then make the following attack", which implies to me that the push portion of the action is not part of the attack and thus would not trigger her sprint (but she would still get to sprint before the attack was rolled.) Is this correct? This also suggests a more general question about whether a power that includes an attack is considered an attack as a whole, or only the actual attack roll portion, although as far as I know, "Drawn to the Flame" is the only power this would apply to (I don't have the expansion yet).
Hypersonic assault is not an attack, but lets you make an attack that ignores range against each enemy passed through. I wonder if the sprint could make such an attack "impossible". While Hypersonic assault doesn't explicitly say it ignores line of sight, it seems like it probably does (or that line of sight is figured from the targets own location, which could make the sprint work if Wraith jumped over a wall). The FAQ does say that Hypersonic Assault "does not inherently ignore changes in elevation", but I think that's referring to the number of hexes she's able to move with the action (In other words, that she doesn't have Mobility for the action unless another power gives it to her).
"Impossible attacks": Being out of line of sight, out of an attack's Area, or violating another restriction of an attack (like Melee) all make an attack impossible in this context.
Slip into Shadows triggers before the attack of Drawn to the Flame, but after the Push.
Hypersonic Assault is unique in that it makes a multi-target attack with a different Origin for each target. Slip into Shadows will probably make that attack impossible because all of Tachyon's attacks are Melee.
Hypersonic attacks targets on spaces Tachyon just passed through.
Once Wraith leaves one of those hexes she is no longer a valid target, and the attack is impossible.
Apparently Wraith can dodge faster than the the speed of sound.
Interesting. The text of Hypersonic Assault never actually says which hexes the attacks are made from (and kind of implies that they are made from the ending hex, since it says she moves and then makes an attack against each enemy she passed through). My intuition suggested basically the behavior you described, but I'm not sure everybodies would. I wonder if Spiff would consider adding this to the FAQ for that power.
This was discussed in playtesting but never officially answered. It is wierd to think of Melee attacks being made from range, or Melee attacks being made from one space, but requiring line of sight to another space.
The way the card is worded and the rules on melee attacks Hypersonic Assault should not work. Range has nothing to do with whether an attack is melee or not, melee attacks require adjacency, and still use range as normal, ignoring range should not cancel the requirement of adjacency, any more than reach given to omnitron should cancel rocket stomp's melee attack status.
1. We know that Hypersonic Assault is intended to hit targets that Tachyon is no longer adjacent to. But by wording and the attacks that Tachyon has available it cannot.
2. We do not know if it is intended to require line of sight, since melee attacks cannot under normal circumstances fail to have line of sight, by rule they have line of sight, because two adjacent targets always have line of sight. By wording the answer is yes, it requires line of sight.
3. Because of things we don't know, we can't say for certain whether the attack whould hit Wraith after she sprints or not. By wording, and assuming that the melee status is cancelled, you would have to say that she avoids the attack only if Tachyon loses sight from the hex she ends her movement on.
The way I have played it is to treat each attack as being made as if tachyon had just left the hex the current target is on. That makes sense with how it should work thematically, and doesn't require Tachyon to stay in line of sight of targets she punched.
The attack happens on the hex the enemy character was on (consider Range as 0 as if Tachyon was making the attack on the same hex as the enemy). Once Wraith leaves that Hex with Slip, the attack cannot be made because it is essentially still a melee attack.