It is possible to remove the Depthsuit on the tile immediately before fighting the Janeria and save (I did this to equip Goo Armor for the fight) and then enter the Janeria fight without dying to the pressure. However, if you then lose to the Janeria and try to load that save, you will immediately game over due to being outside without a pressure suit and have no way to salvage the save. In theory this should also be possible if you unequip the Depthsuit on any exterior tile and then save before moving, resulting in the softlock.
Possible fix: Make a prompt to re-equip the Depthsuit (an 'Are you sure you want to do this?' message maybe) if the game detects them outside without it? I realize this is a niche scenario, and if you keep frequent backups (I do not, I'm the type to always overwrite the same file cause I hate clutter) it is not as bad an issue, but it could help somebody else who does an equally stupid thing as me.
Possible fix: Make a prompt to re-equip the Depthsuit (an 'Are you sure you want to do this?' message maybe) if the game detects them outside without it? I realize this is a niche scenario, and if you keep frequent backups (I do not, I'm the type to always overwrite the same file cause I hate clutter) it is not as bad an issue, but it could help somebody else who does an equally stupid thing as me.