At that time his heart was still partly there and not entirely "elsewhere" yet.
Him being capable of summoning the Keyblade and opening a light door serves as an indicator that he's still alive and struggling.
I'm not going to spoil it, just play on with BBS and eventually you'll see what happens with Ven's heart when it truly leaves its body.
Appreciate the reply. I posted this having already finished BBS actually but I was just revisiting it. Are we just supposed to assume that his heart was still â€œpartly thereâ€ bc of his ability to summon the Keyblade? Are you referring to Ven entering Soraâ€™s heart as it â€œtruly leavingâ€ or? Does that mean hearts can partially leave bodies? Or do hearts have a rigor mortis sort of thing where they can still function briefly even after they are removed?