Flustered, Lev and Titania stared at the door where Dmitri was a moment ago. As for Dmitri, he gently closed the door behind him, sneaking out of the Sick Bay while causing a commotion in the common area. He made sure to lock the door just in case someone else wandered accidentally and see the two of them doing this and that— or at least that's what Dmitri assumed after seeing them in a suggestive position.
There was no time to waste. In haste, Lev grabbed Titania by the hand and prompted her beside the bed, making her stand up. He also got up, dusting himself while avoiding Titania's eyes. If they let the situation get the better of them, they knew that Dmitri was going to misunderstand them for some time.
That's why Lev decided to exit the Sick Bay with Titania. That way, the interval between the misunderstood scene and them rejoining the group would be minuscule, which would then make Dmitri conclude that nothing happened.