Good thing I grabbed everything before I got locked in here.
Fury Green and Volt Forge also lock you in before you start, but also, Fury Green is the very first area and Volt Forge is where you get the transit to go everywhere else. Ice Belt also locks you in, but only after you’ve made fairly significant progress, and you probably can leave to grab stuff before fighting the boss. As far as I’m aware, though, Flare Pool lets you leave whenever you like. The only thing really keeping you there is the pair of allies that probably wouldn’t be too happy if you left without them. But this time, the elevator simply locks in place right after you enter. There is no leaving if the stuff ahead is too hard, so I’m really glad I went out of my way to grab nearly everything. (I missed one thing that Spider Ball unlocks in Sol Valley. Hopefully that won’t be a big problem!)
Something Samus hasn’t had the opportunity to work with prior to this game is allies that are geniunely helpful. They don’t have infinite health, but healing them with the Psychic Visor doesn’t cost you anything, so they’re effectively combat boosters. You just don’t want them to totally die, so protecting them is still a bit of a chore—it’s just not the typical escort mission of someone who’s completely unable to fend for themselves. Now if only they’d quit doing the heroic sacrifice thing! The first made sense, but the second: they’re burrowing through solid rock to get in there. Sticking a drill in the open hole is not exactly going to keep them away!