It's not a suicide attack, it's a Mechacide attack The MechWarrior would hopefully eject.
If you read the rules for both ejection and self-destruct, it's still suicide. There is absolutely no way for a pilot in a tabletop game to eject from their mech and get out of the blast radius before it blows. Eject or not, you're just deciding if you want to be a puff of ash in your mech's wreckage, or a puff of ash next to it.
...okay, there's *one* way. IF there's a hardened building within two hexes of the warrior's landing point(which is always the hex immediately behind the mech they just abandoned), AND they didn't pass out or die from injuries during the ejection, it's possible to get in there and be protected from the blast. I do mean
hardened, too. Anything less and the damage will still kill the warrior inside. Better hope the folks already in there are friendly.