This is in regards to Mutants and Masterminds 3E Deflect.
Action: Standard • Range: Ranged • Duration: Instant • Cost: 1 point per rank
You can actively defend for characters other than yourself, deflecting or diverting attacks against them at a distance, and may be able to more effectively defend yourself, depending on your rank. See the Defend action in Action & Adventure for details. You use your Deflect rank in place of an active defense. You still add 10 to a Deflect die roll of 10 or less, for a minimum roll of 11. Deflect modifiers are limited by power level. Like a ranged attack, if you Deflect at medium range, you have a –2 circumstance modifier on your check. At long range, you have a –5 circumstance modifier. Range is Measured from you to the target of the attack you are deflecting.
I had a player invoke Deflect with the idea of staving off the next attack coming in and there arose a discussion on how to interpret who gets defended. My ultimate decision as a GM was that the spirit of the description was that you choose a single target for the Deflect, and they get the bonus, but you do not. So effectively, it lets you do a Defend action and then have the effects apply to that person until the beginning of your initiative count. As regards the picking of targets, that works for a Readied action, picking a situation and being able to preempt it.
There used to be a forum for asking the game designer, Steve Kenson, for clarifications, but that hasn't been available for a long time. There was some discussion on the official boards (link currently dead), but nothing that I felt directly answered my question.
Best Answer
Nothing in the Power limits the effect to a single target.
Deflect
Contrast this with the Defend action, which is explicitly limited to the defending character.
Defend
A character using Deflect can defend against any attack that can be accurately perceived within the power's range, regardless of target or attacker. Subtle effects cannot be deflected unless the defender has some ability to detect them, and the limitations of range, area attacks, perception range attacks, and attacks against other defenses are already mentioned in the power.
Note that certain power descriptors may limit the effectiveness of Deflect, especially when interacting with other descriptors, but that's too situational to be covered in this answer.
Also of note is that the GM adjudicates all unclear or unusual situations, so the GM is correct by definition. And if a particular ruling is more fun for the table than another ruling then the more fun option is more correct. Again, this fact is too situational for the scope of this answer.