Well, I'm going to resist the temptation to give a funny answer, and "play it straight" this time...
To me, this looks like a pivotal scene from probably half of the fan fiction stories I've written! Kara (as Supergirl) gets trapped somehow by the "bad guys" she's pursuing - either by kryptonite or high-voltage electric charges. Or else, by Luthor's favorite scheme: if Kara tries to break out, she will set off a huge bomb or release a cloud of toxic gas and kill a lot of innocent people. But the villains don't know that Kara has her cell phone hidden in a secret pouch in her boot. So as soon as they're gone, she speed-dials Alex (who is seen here taking the unexpected call!). Of course, Alex immediately gets in touch with other members of the Supergirl Team, and they devise a viable plan to get Kara out safely. (Hey, Brainy has a 12th level intelligence - he ought to be able to come up with something pretty quickly