Ignoring the weight of all existence, crushing down on him was much easier than it sounded. Lex was really too experienced in being uncomfortable, extremely comfortable, from being cooked alive to having no skin, to let some weight stun his mind - once he got over the initial shock.
He was entirely focused on bonding with Lotus, and the process was longer than it had seemed. When Lex bonded with Pelvailin, he had to put in a lot of effort, but this required even more!
At least he did not need to supply the energy to facilitate the bond on his own, or else he would have gone broke. The liquid, which had by now filled half the tub, stopped increasing, and then eventually began to drain.
As Lex built the bond, Mateo explained the reasoning to him. The projection spoke not through spirit sense, which had the potential to distract Lex, but through some other means that touched a much deeper part of Lex's mind, automatically transmitting the information to him.