'… intended for introverted people to give a kind of performance for themselves…'

'No one here is saved, no one totally lost.'

Yeah, or sleet, OK, better.

Snow.

'A crime scene, too, is deserted; it is photographed for the purpose of establishing evidence.'

'Public', i.e., for the grownups.

Even some kinds of tactlessness call for tact.

'Tact', mid seventeenth century (denoting the sense of touch): via French from Latin tactus 'touch, sense of touch', from tangere 'to touch'.

Tact is not just having a light touch, but knowing when to use a light touch, and when not to—and having the control and sensitivity to be able to touch lightly. Which means, not to disturb—not to stir up.

Touch here has to do with intimacy, with privacy, with what is concealed or (better) what is visible but unacknowledged.

Snow.

—They're exposed when they talk on the phone. By picking up the phone, they risk exposure.