I have a feeling if Maxine saw them they wouldn't have to call her over, she'd just come running like "OH HEY GUYS! :D"

Also, is the poor kid the only one with a car??? Mario could be walking the girls home(maybe he was originally with Olivia and someone else who left, then Max spotted them and came running?), and then as the UFO is landing, Jason and Iikka are riding by in Jason's mazda on the way to Jason's (because his mom is working at the diner so they are going to chill at his place without parents around), and he slams on the breaks and they get out because its a freakin UFO.