For everyone saying Fortress are idiots: this is a loan and the amount is conditional. That means 2 things:

1) If Theranos fails, Fortress can claim its assets.

2) The money is not released until certain milestones are met.

So either Theranos misses the milestones, folds, and has Fortress take over its assets, OR Theranos meets the milestones and is actually a valuable business.

Depending on the terms, Fortress could have easily structured this deal such that they win in either scenario. I would imagine that Theranos was desperate ("distressed"), so the terms are likely pretty onerous.