In-universe, he built up momentum by pointing himself downwards and diving towards Claire. Claire is positioned horizontally, so she's supposedly slowing herself down, similar to how a parachute would. He has less "resistance", so he goes faster than she does.
Out-of-universe, this obviously doesn't make a ton of sense. But it's a very common occurrence in action movies and tv shows, and you're supposed to apply a bit of suspension of disbelief. See the TVTropes page on Variable Terminal Velocity:
How fast you fall depends on who and what you are.
The wacky world of TV physics seems to postulate, among other factors,
that how fast a person or object is pulled towards the ground is a
function of how heroic they are, and not the constant acceleration of
gravity (9.8 meters/second^2) that the rest of us have to deal with.
For instance, no matter how tall a cliff or building is, should a
character or a fragile vase fall off, there will always be enough time
for the Hero to leap after them, catch up to them in mid-fall, and
rescue them.
This is a gross violation of physics in most cases. One object
accelerated by gravity alone cannot pass another such object that was
dropped before it. Neither the size of the objects nor the relative
virtues of them can change that. Galileo and Newton both famously
showed this, and Dave Scott confirmed it much later in a near-perfect
vacuum.
Even factoring in wind resistance, you'd need to fall a very long
distance (as in thousands of feet while skydiving, not the hundreds of
feet out an apartment window) for that effect to be workable in your
favor. And you also have to make sure the wind resistance is, in fact,
in the rescuer's favor (by, say, falling forward and keeping your arms
and legs together as the rescuer while the person in danger is falling
flat with their limbs hanging out).
It only gets worse if the falling rescuing hero completes the rescue
with help of Building Swing gadgetry like grappling hooks or ropes: in
Real Life, a falling person trying that would be more likely to lose
the rope than save the person on the other end.
Then again, you're watching a show about a blind guy who fights crime by listening to heartbeats, so you're not really supposed to think too hard about this stuff.
