I always thought it strange that ejecting for any reason caused insta-fail. What if your character happens to be geared up with a hand-held "nova-beam 9001", a full set of Thracian Power Armour, and 20 points in Vitality? To all intents and purposes, a miniature, slightly reduced mecha with attitude, and probably geared up with some pretty nifty hover/flight jets to boot. You could probably finish the job yourself if you'd caused enough damage to start with, or wait for your lancemates to do so whilst staying out of harm's way.
Heck, what about the alternative, where you're a 5 Body librarian with a flight suit? Why should you get an easy out? Escape the map or die foo'!
In general, I'd sooner have a "surrender" option in addition to an "eject" one. If you surrender (and have there a possible morale based surrender just like , the enemy then chooses whether to let you get bounced to world map, capture you (new pseudo-missions: Escape from being imprisoned by your enemies and maybe recover any lost rep, or wait for your faction to pay the ransom and suffer even more reputation loss).
In fact, I'd prefer ejected pilots to stick around in general, and have Mecha hijacking as a viable combat maneuver (busted mech? Forcibly enter an enemy mecha and attack the pilot directly to knock them out of the mecha -and damage them directly of course- and then have a means of entering and piloting the mecha), but these are matters for game mechanics I believe.