I've duped twice out of like 100 attempts now. Can someone tell me what i'm doing wrong?

1. Log into A
2. Log into B
3. Wait for screen B to say "connecting..Connected!" and then go into nexus with A
4. Screen shifts to B. B is in the vault, Screen A is still trying to connect to vault.
5. Drag items from chest into inventory.
6. Wait for the Connected! sign on screen A
7. CTRL+Q as fast as the human nervous system will go