That's the challenge and the purpose of it. It even warns you that it's extremely dangerous to solo for good reason. That's the one single skill that puts Hilla apart from other bosses so it should be kept (unless you want it to be another mindless boss that just stands there doing nothing).
there should at least be a way for you to escape without breaking out (Houdini.)
That's her design, for her not to be solo'd in the first place. It was designed for party play and that's what happens when you don't have the right resources. This is no different to the 1 hit ko's Arkarium does, and heal received by his minions (cannot kill without a mage). By asking to remove the cage or escape is equivalent to asking Nexon to make CWKPQ soloable.
It's just the design itself, and there's not much to argue about it.(less)
the flaw in the design is that it doesnt account for actual class skills and requires other players use the attack key, which is terrible design for gameplay of current maple (and was pretty bad design for when hilla was first released tbh), and that's the only part of it that should be changed, cause even if you enter with a party of 6 there is no way they will be able to help you in time.
otherwise, solo you can avoid it entirely if you time your jumps right.
is Nexon NA willing to reveal the % chance of getting things in their randomized cash items (things like Premium style boxes, Andersons box, Golden apples, Philo books, Marvel Machine, … (more)Gachapon.. etc)
at this point, where the korean, Japanese and even Chinese variants at least reveal the % chance to get items from their randomized cash items (albeit through laws) I think it would be nice if the NA branch just published these out of respect to the players, following the trend that players (and many online gamers in general) want, and it would also be a show of good will as, as of yet, there is no law that requires you do this in the NA region, but it sucks to see that it would require twisitng your arm (through the law) to get this information. (less)