Their daughter-from-the-future who was under strict instructions to come wake them up if they hadn't checked in within an hour.
The plan was only to go one level deep, they wouldn't even need a kick, just the timer on the PASIV running out, but Arthur had also set both his watch and his phone alarms at three five minute intervals each, just in case. It was probably overplanning, but caution was easy.
He nodded, settling back in his own chair, having double-checked the timer, "Starting with raw dreamspace, or a bare-bones construct?" He had both, he just needed to know which to drop them into.