Given:

  boot: linux rescue

The first two (anaconda?) screens - language and locale (?) - say
nothing about being in rescue mode - they give a strong impression
that, instead, a standard install is being performed.

Only the third screen, which asks where the rescue media is to come
from, gives a hint.

That rescue mode has been selected needs to be clear from the start -
that way the user gets a warm fuzzy that they are on the right track.