[Post-game 'conversation' with the G-Man, takes place in helicopter, flying through a desert canyon]
G-Man: So, Corporal Shephard, we meet at last! Please, don't think that I've been avoiding you, a great many matters require my attention in these troubled times. I *do* hope you understand. Now, I require a further indulgence on your part. I cannot close my report until every loose end has been tied up. The biggest embarrassment has been Black Mesa facility... but I think that's finally taking care of itself.
[Bright flash of light, implying that the bomb you disabled has in fact gone off]
G-Man: Quite so.
[Another flash of light. Now, the helicopter is flying through Xen]
G-Man: But there is still the lingering matter of *witnesses*. I admit, I have a fascination with those who adopt and survive against all odds... they rather remind me of myself. If for no other reason, I have argued to..."preserve" you, for a time.
[Another flash of light. Now, the helicopter is flying through a pitch-black expanse with few tiny lights passing by]
G-Man: While I believe a civil servant, like yourself, understands the importance of discretion, my employers are not quite so trusting. And rather than continually subjective to the *irresistible* human temptation of "Telling All", we have decided to convey you somewhere you can do no possible harm... and where no harm can come to you. I'm sure you can imagine there are worse alternatives...
[Fade to Black]
Ending Titles: Subject: Shephard. Status: Detained. Further Evaluation Pending.