level -8 does have an exit, however as of this update the only way it leads is level -9, which doesn't have an exit yet but it's going to be in the next update. level -8's exit is hard to get, but you need to go a specific route, which all the pathways have signs over them with a number, try looking on the mghc wiki for level -8 and you'll see there is a few you can do, (however i did shorten the path so you won't have to do as many numbers as the wiki shows) i might add some sort of hint to what the number is however. i also will fix level 7's exit to level 8 to be easier to find. level 2.1's flash is hard to avoid, but you have to look at the lights, make sure they aren't flickering, and then you can run through, just be careful for each one, since it doesn't show the flickering until you're a few tiles close.
thank you for your feedback, i will take these things into consideration within the next update.