Unfortunately you can still easily eject from your mech. When you see yourself close to dying just power off and eject after.
That's not ejecting, that's disembarking.
If you can do that without your mech exploding before it even stops moving (to power down) you either had a pretty good amount of health left or weren't in any real danger
Ejecting is "lololol 0.1% CT left, nao I'm 100 meters above any danger"
Disembarking is "wait to stop, wait to power down, fall out of cockpit into direct line of any missiles coming at mech"
One is clearly much easier to do and thereby frowned upon, while the other isn't as much of an "instant second chance button" and can actually be worse for your score if tried in the direct vicinity of any aware enemies