When there's no possible way to avoid annihilation
https://www2.pic-upload.de/img/33282511/quadra.gif
The enemy was all like: https://68.media.tumblr.com/9e97baca10d9a7e40bab65be57aa802c/tumblr_inline_ncz1ysdga51ske89b.gif
You'd either try avoiding Morde to make Zilean ult run out, resulting in him killing you all... Or you'd focus him, giving him a revive and more time for the enemy to collapse on you...
That, ladies and gentlemen, is delightfully painful.

with a
or
. Good boosts to movement speed to catch enemies and shield and revives to help cover your weakness of getting locked down and blown up.
'd