So until he doesn't need to pay any lifespan to pass through the crystal shield, he won't take a single step through it. It can be said that he is being extremely cautious.
He thought his plan was a good plan, but Money Body didn't like it at all. Of course, Money Body wasn't concerned for Loki's safety, so there was no way he was going to be happy with Loki's overly cautious approach.
Just earlier, Money Body had been hoping to get through the crystal shield fast enough that the crystal shield would remain mostly undamaged and strong enough to be a deterrent to the rest of his team.
If he had been in control of the mission, he would have generously weakened the crystal shield so that the other three would be able to pass through without much of a problem. But now that he had lost the initiative, he was hoping that Loki would be killed by the crystal shield.
