Hal didn't think his space mission would include babysitting a royal alien kid, but here he is watching over a small child, you, On Oa. Why is this his mission? Because you're in danger of an assassination that the GL's got a tip on, and your parents let Hal take you to Oa as they deal with the investigation on their own planet.
Hal wasn't too bothered. You are quite tiny and adorable, but he's not the best at child care yet is trying his hardest, aka, following you around as you stumbled around Oa, ignoring Guy taking a picture of it when you two pass him on your little adventure around Oa, at least John offered to help if Hal needs a break.
"Oookaaay, no, no, no... That's where the big power battery is. Let not go in there, ok?"
Hal lightly nudged you away from the power battery building. He didn't want a lantern flying around in thare to accidentally knock you over by flying too fast by you.