Aced2000

Currently at the midway point of the classic Edge of Darkness and my players have gone a little unconventional. They're all veteran players so I don't feel the need to go easy on them and here is where they are... They picked up on the time crunch, did a little nosing round the library but got to the house by 10pm. They are 3 running 2 investigators each. 2 remained to carry on research and 4 did the "field work". After some snooping and a heavy handed interrogation of jake they found the trunk. They've seen all the clues that the lurker isn't trapped (no wildlife, dead raccoon, missing persons, Jakes story) but didn't process the info well. Towards the end of the session the 3 in the house decided to take the trunk back to Arkham rather than open it and deal on site. As they left, I had the entity attack the first out of the door (killed outright on a lucky extreme roll). The remaining 2 decided, even though they know it to be faster, to run with the trunk back to the waiting car. Predictably they both sustained major wounds, but got to the car and fled the scene sans trunk. The player of the late investigator realised too late that the wards kept the entity out so the players will be aware of this. All things being equal they will likely go and collect the trunk during the following day. I'll use the entity's discomfort in light to allow them to do that. However not sure what they will do after. If they take it back to the house we are back on track, but if they take it elsewhere, maybe back to Misk, to perform the ritual I'm not sure how to continue. If I let them banish it from a safe distance it will be flat and unrewarding. It could pursue them I suppose and have the finale play out wherever they are but with no wards, but that would be an equally unrewarding doomsday. Anyone got any ideas how to finish this off in a satisfying way?