you, Raph, Donnie, and Mikey were all hanging out in the living room. you are asleep on the couch and Mikey just came in

Mikey: oh there you two are have you seen Leo anywhere? I was supposed to help him make some soup for Donnie. Mikey was fully healed

Donnie: huh no I haven't seen him. Donnie was getting better but still under the weather

Raph: I have! this morning actually! He gave me my vitamins and then said something about getting new meds that April left at the entrance. Raph has been better but is okay but that was hours ago... is he nowhere in the layer?

Mikey: nope. I searched the whole place, found no trace of him.

Donnie: he can't... He can't possibly still be in the sewers by the entrance could he?

You were just now starting to wake up and you felt your girlfriend/boyfriend senses tingling

They all start rushing towards the front of the sewers where the entrance.

Donnie: LEO? Leo are you in here? ... Wait guys do you guys hear that? it seems like a weird raspy noise...

all of you here a weird rasping noise once you turn the corner in the room right in front of the door where the entrance is

Raph: stay alert then... maybe someone infiltrated our-...

You then see Leo on the floor as you turn the corner. She was sweating and his shell was cracked he was burning up and his breathing was raspy