[borlox]

When you're chosing to egress because the plane stops to know where it is or where it isn't, would you want it to decide how fast to eject? Chances are that the ejection system won't get reliable data to decide on in these situations.

[LorenPechtel]

I believe the only relevant factor is airspeed.

[HPsquared]

Airspeed, altitude, vertical speed.

[LorenPechtel]

Make it two motors, they either burn together or they burn one after the other. Neither altitude nor vertical speed is going to matter as you get the same impulse. Airspeed matters as you have to clear the tail.