Does 危机 really mean both crisis and opportunity?
Victor Mair has an essay answering your question directly:
Danger + opportunity ≠ crisis, how a misunderstanding about Chinese characters has led many astray.

[...] Like most Mandarin words, that for “crisis” (wēijī) consists of two syllables that are written with two separate characters, wēi (危) and jī (機/机).
[...] While it is true that wēijī does indeed mean “crisis” and that the wēi syllable of wēijī does convey the notion of “danger,” the jī syllable of wēijī most definitely does not signify “opportunity.”
The jī of wēijī, in fact, means something like “incipient moment; crucial point (when something begins or changes).” Thus, a wēijī is indeed a genuine crisis, a dangerous moment, a time when things start to go awry. A wēijī indicates a perilous situation when one should be especially wary.
[...] jī added to huì (“occasion”) creates the Mandarin word for “opportunity” (jīhuì), but by itself jī does not mean “opportunity.”