Your original goal was to get into the body of one of the cheerleaders, and despite the recent detour your trip has taken, that's still exactly what you intend to do. Fortunately, he dropped the majority of your body in an unsecured bin. You decide that it's a good idea to get lost before Marc can do any more of his tests on the non-jarred piece of you, and you begin to navigate your way out of the plastic tub.
The fact that you're seeing the world from two perspectives at all times is incredibly disorienting, however, so in the beginning your efforts don't amount to much more than writhing around and flopping about. However, you find that if you imagine each perspective as a single, independently operated eye, like how chameleons have them, then it's much easier to direct yourself and, as a result, stay oriented. You use this new method to stretch up the side of the tub, and pull your wormlike body over the side. Balancing carefully along the side of the tub so as to not tip it (and end up making a bunch of noise), you flop onto the carpet of the bedroom in a single fluid move.
You stop and listen carefully for a moment. You can hear Marc's breathing, which is still quiet and regular. Good, he didn't hear you leave the tub. You inch your way toward the door, and easily slip under it.
In the hall now, it is still very dark, and therefore not easy to see. You do recall, however, that both of the girls sounded like they were in the room a bit down the hall and to the left, so you inch in that direction. Sure enough, you can make out another door in the darkness, and you wriggle underneath it.
Two sets of slow breathing, higher pitched than Marc's, tell you you're in the right room. You're not sure which girl is in which bed, but you don't feel particularly picky. If you have no problem controlling multiple of your worm body, there's a good chance you can also control multiple humans as well. If things got sticky then you planned to just force yourself into the other girl.
Hopefully it didn't come to that, though. All of this change was a bit hard to swallow (pun intended), and having to wrestle while controlling multiple bodies sounds really hard. Either way, you figured it would be best if you got a move on and got into one of the girls.