To be fair to Reed's various untested inventions- they usually acted very well under pressure. Usually. Though Johnny did have several very good points.
"No, you're right. Tony may let me observe it but I doubt he would be incredibly willing to have it replicated, even by the Fantastic Four." As possessive as Reed was of several of his more powerful and unstable inventions (unstable molecules, the ultimate nullifier, etc.) he could only imagine that Tony would be doubly so given that this device was also keeping him alive. And Reed was above pilfering technology that didn't belong to him, even if he could replicate it.
"Zero-Point is..." Reed shook his head, staring off into the middle distance, "months, maybe years out, depending how much time I can devote to it..." His mind briefly fluttered back to his recent conversation with Susan, regarding certain aspects of family life that were (hopefully) about to put much greater demands on his time. He didn't share these concerns with Johnny though-- he and Sue had agreed to speak to the rest of the family once they had good news to share.
If he threw himself into it now though, then they'd have a deadline of at least nine months to---
Reed pulled his attention back to Johnny's questions. "Hm. Provided that we can get applicable results, we'll start small-- perhaps running flashlight, then a generator and work our way up to vehicles; how do you feel about Go-Karts?" A Go-Kart would be just for a testing of the Zero-Point Energy as applied to vehicular technology... and also easy to stop, should it get out of control.