Question about Brainstorm

Hello everyone,

I have a question about the yellow ability "Brainstorm" - in its game text, it says the following:

"Attack using [power]. Hit one target using your Min die, another target with your Mid die, and Boost using your Max die."

Does the Boost apply to the Hero using the power, or someone else (like an Ally)?  

The Boost can apply to any target, since it does not specify a target.