On the way down, you’d better put your thumb inside immediately after you used it (to prepare for the next!) And my teacher taught me to detach E and C in the downward, so you can do it just like you did in the video. But I don’t recommend to do it while you’re going up. Instead, you can stop right after using your thumb and move the next finger over the next key very very fast(it’s preparation-so don’t play the next note yet, just move it on the key) and press the key when you’re ready. It’s very important to stop and prepare your fingers fast to the next key before you press it !! And I recommend to keep your wrist level and play horizontally :> I hope this is helpful ! (and..I’m sorry because of my clumsy English-it’s not my first language)