Washcoll2004, the Q already does longer than 2 seconds with elec shutter. We just have to trick it. I do it often with adapted teles at night. Set Q to manual exposure 2 seconds. In menu select multiple exposure 9 shots, and Uncheck the box about adjusted exposure. 9 shots at 2 seconds each gives 18 sec total exposure. I try to use wireless remote to keep from moving Q- but it is not required. The waterproof remote works much better than remote F.
Be sure you have done Q firmware update, otherwise it tends to lockup.