"There's another function these devices have that Time Agency ones don't have," Lena said. "If you can get into the White House and near enough to our 'beloved' president Jake can lock onto your device's energy signature and transport to whereever you are. It uses a lot of energy though and you'd have to make sure when you want to leave you're in a safe enough place I can transport you back, otherwise I can't guarantee you can use your device to get out of there. Do you think you can do that?"