More specifically, Foggy finds an injured, half-dead Elektra (possibly after her iconic ... "encounter" with Bullseye) and, against his better judgement, knowing that if he called an ambulance she'd be in trouble, decides to take her in and patch her up himself. Mostly because he knows how much Matt loves her.

When Matt thinks Elektra has died, however, Foggy hides the truth from him, reasoning that she's brought him nothing but pain (and maybe a little bit of jealousy is involved as well).