The Scaresville experience is designed to take approximately an hour from the time when you enter the Scarezone. On certain nights, you may be held up by slow-moving groups ahead but we try to minimise the effect of this.
If you are booking a taxi to collect you after the experience please note that you might not enter the ScareZone until the end of the timeband that you have booked for, so please allow for entering then, for perhaps not exiting for an hour and a quater and add another ten/fifteen minutes for going to the loo and getting back to the entrance. May be better for you to wait for the taxi than to have the taxi waiting around for you or leaving the driver having decided you were not coming.