Question about leveling

[Greco12]

Recently I watched parts of a Lunar SSSC play through and I noticed something near the end. Here's a screenshot I took from this playthrough. As you can see, the player somehow managed to get everyone ahead of Alex, with Kyle three levels ahead.

Now I know that Jessica and Mia usually lag behind one or two levels because they get sick during the Black Dragon Fortress portion of the game*, and the game automatically levels Nash up to Alex's level when you get him back after he betrays you. The player doesn't show all the grinding he did to get the characters to their respective levels, and this video is from his old channel.

Someone told me that you can level certain party members ahead of others by letting the rest die in battle (e.g. level Jessica and Mia up by letting the guys die in battle and letting the girls finish off the monsters), but I find this very hard to believe and I've never tried it out.

I know it's possible to get everyone up to the same level (assuming you didn't go crazy with grinding in the BDF while the girls were out of commission) by the time you fight Ghaleon, since it amounts to a lot of patience and grinding. Any idea of how this guy was able to level everyone above Alex?

*I'd like to take a moment to ask an additional question: how come they don't level the girls up to either Alex's level or at least average their levels out with the guys' so that they don't lag behind? The game usually levels returning characters up to his level or at least close to it, like they do with Nash. I l know it's possible for them to catch up (although their actual xp will be lower than the boys), but it seems impractical to let the healer and better mage lag behind given what a huge asset they are to the party (healing and, in Mia's case, destructive spells and helpful buffs).

[Kizyr]

Running? I actually can't remember this offhand, but can individual people run from battle?

With EBC, if someone dies, they still get EXP (which is a change from the Sega CD originals), but I remember not being able to replicate that with running because off being unable to get individuals to run separate from the group. In SSSC, could you have Alex flee battle leaving the rest behind? KF

[Sonic#]

I remember being able to have individual members run.